DOE-HDBK-1122-2009 Chg Notice 2, Radiological Control Technician Training (Part 5 of 9)

Part 5 of 9 Radiological Control Technician Training Site Academic Training Instructor’s Guide Phase I Coordinated and Conducted for the Office of Health, Safety and Security U.S. Department of Energy DOE-HDBK-1122-2009 Radiological Control Technician Instructor’s Guide ii This page intentionally left blank. DOE-HDBK-1122-2009 Radiological Control Technician Instructor’s Guide iii Table of Contents Page Module 2.01 Radiological Documentation ............................................................................2.01-1 Module 2.02 Communication Systems ..................................................................................2.02-1 Module 2.03 Counting Errors and Statistics ..........................................................................2.03-1 Module 2.04 Dosimetry .........................................................................................................2.04-1 Module 2.05 Contamination Control .....................................................................................2.05-1 Module 2.06 Airborne Sampling Program/Methods .............................................................2.06-1 Module 2.07 Respiratory Protection ......................................................................................2.07-1 Module 2.08 Radioactive Source Control .............................................................................2.08-1 Module 2.09 Environmental Monitoring ...............................................................................2.09-1 Module 2.10 Access Control and Work Area Setup ..............................................................2.10-1 Module 2.11 Radiological Work Coverage ...........................................................................2.11-1 Module 2.12 Shipment and Receipt of Radioactive Material ................................................2.12-1 Module 2.13 Radiological Incidents and Emergencies ..........................................................2.13-1 Module 2.14 Personnel Decontamination ..............................................................................2.14-1 Module 2.15 Radiological Considerations for First Aid ........................................................2.15-1 Module 2.16 Radiation Survey Instrumentation ....................................................................2.16-1 Module 2.17 Contamination Monitoring Instrumentation .....................................................2.17-1 Module 2.18 Air Sampling Equipment ..................................................................................2.18-1 Module 2.19 Counting Room Equipment ..............................................................................2.19-1 DOE-HDBK-1122-2009 Radiological Control Technician Instructor’s Guide iv This page intentionally left blank. DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-1 Course Title: Radiological Control Technician Module Title: Radiological Documentation Module Number: 2.01 Objectives: → 2.01.01 List the types of records/reports that the Radiological Control group is responsible for maintaining at your site. → 2.01.02 Describe the types of records and reports used at your site by the Radiological Control Group, to include but should not be limited to: a. Radiological Work Permits b. Survey Reports c. Analysis Reports d. Radiological Deficiency Reports e. ALARA Documentation f. Exposure Reports

→ 2.01.03 Explain the requirements for the records management system, such as QC, auditability/retrievability, management information at your site. References: 1. 10 CFR Part 835 (2007) "Occupational Radiation Protection". 2. "Radiological Control Standard," DOE-STD-1098-2008. Instructional Aids: 1. Overheads 2. Overhead projector/screen 3. Chalkboard/whiteboard 4. Lessons learned DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-2 I. MODULE INTRODUCTION A. Self Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation A good Radiological Control Program must have a sound documentation process. RCTs are involved daily in creating records through surveys, RWPs, and procedures that give a history of actual conditions and operations. C. Module Overview 1. Purpose and requirements 2. Radiological records management program 3. Radiological record keeping standards 4. Types of radiological records 5. Records management 6. Radiological reporting D. Introduce Objectives II. MODULE OUTLINE NOTE: Most of the material for this section will come from specific site procedures. The instructor must be thoroughly knowledgeable in and have available for student use, procedures for RWP's, Radiological Occurrences, Records Maintenance, Inventories, and O.H.: Objectives DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-3 any other RC procedure related to administration. In addition, any other procedure or procedural change can be covered in this section. A. Purpose/Requirements Discuss the purpose and requirements for records and reports at DOE facilities based on 10 CFR 835 and DOE RCS. Discuss any additional site requirements. B. Radiological Records Management Program 1. Discuss the types of radiological records that should be included in the records management program. a. Quality Control b. Audits c. Records retrieval d. Management information 0. (Insert site specific information here.) C. Radiological Record Keeping Standards 2. List the standards for record keeping. 3. Discuss the justifications for record keeping standards. D. Types of Radiological Records 1. Identify and define the record categories: a. Employment History Records Objective 2.01.01 Ask the students why it is considered necessary to include facility, specific location and function on documentation. Ask trainees why it makes sense to initial and date corrections. DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-4 b. Personnel Radiological Records c. Medical Records e. Radiological Training and Qualification Records f. Instrumentation and Calibration Records g. Radiological Control Procedures 2. (Insert site specific information here.) E. Records Management 4. Discuss storage requirements 5. (Insert site specific information here.) F. Radiological Exposure Reports 1. Purpose 2. Process 3. Examples of filled-out exposure reports III. SUMMARY A. Review major points 0. Purpose and requirements 1. Radiological records management program 2. Radiological record keeping standards 3. Types of radiological records 4. Records management 5. Radiological reporting B. Review learning objectives Objective 2.01.02 Objective 2.01.03 DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-5 IV. EVALUATION

Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% should be the minimum passing criteria for examinations. DOE-HDBK-1122-2009 Module 2.01 Radiological Documentation Instructor’s Guide 2.01-6 This page intentionally left blank. DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-1 Course Title: Radiological Control Technician Module Title: Communication Systems Module Number: 2.02 Objectives: 2.02.01 Explain the importance of good communication. 2.02.02 Identify two methods of communication and be able to determine different types of each. 2.02.03 Describe different types of communication systems. 2.02.04 Describe the FCC and DOE guidelines regarding proper use of communication systems. 2.02.05 Describe general attributes of good communications. 2.02.06 Explain the importance of knowing how to contact key personnel. → 2.02.07 Identify the communication systems available at your site and methods available to contact key personnel. → 2.02.08 Describe the emergency communication systems available at your site. Instructional Aids: 1. Overheads 2. Overhead projector/screen 3. Chalkboard/whiteboard 4. Recommended - radio, telephone, pager, warning alarms, phonetic alphabet handout 5. Lessons learned DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-1 I. MODULE INTRODUCTION A. Self-Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation Good communication skills are essential to an RCT. Each RCT should develop an ability to communicate using both verbal and non-verbal media. This skill will ensure important information is transmitted to the proper individuals in a clear and concise manner. C. Overview of Lesson 1. Importance of communication 2. Methods of communication 3. Communication systems 4. FCC and DOE guidelines 5. General attributes of good communications 6. Contact of key personnel 7. Site communication systems 8. Site emergency communications D. Introduce Objectives O.H.: Objectives DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-2 II. MODULE OUTLINE A. Importance of Communications 1. Clear 2. Understood 3. Received B. Two Methods of Communication 1. Verbal 2. Nonverbal C. Communication Systems 1. Public Address 2. Telephones 3. Two-way Radios 4. Pagers 5. Computer Mail Systems 6. Computer Bulletin Boards D. FCC and DOE Guidelines 1. When using communication systems licensed by the Federal Communications Commission and operated by the Department of Energy, one cannot: Stress importance of complying with these restrictions. a. Use profane, indecent, or obscene language. Objective 2.02.01 Objective 2.02.02 Ask the student to name the two ways to communicate and examples. Objective 2.02.03 Ask students to name communication systems available in everyday use at home and work. Objective 2.02.04 DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-3 b. Willfully damage or permit radio equipment damage. c. Cause malicious interference with any radio communications. d. Intercept and use or publish the contents of any radio message without the permission of the proper authorities. e. Make unnecessary or unidentified transmissions.

f. Transmit without first making sure that the transmission will not cause harmful interference. g. Make any adjustments, repairs, or alterations to a radio transmitter without licensing by the FCC or acceptable equivalent. h. Transmit a call sign, letter, or numeral which has not been assigned to your station. i. Rebroadcast another transmission (i.e., radio station music). E. General Attributes of Good Communications 1. Minimize the use of abbreviations and acronyms. 2. Make all oral instructions clear and concise. 3. Ensure the identity of the person(s) is/are clearly understood. 4. Use clear, precise terminology. 5. Repeat back messages, either paraphrased or verbatim. 6. Speak distinctly and deliberately. Objective 2.02.05 Stress importance of good habits and technique. See Table 1 - "Phonetic Alphabet and Numbers”. DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-4 7. Acknowledge all communications. F. Contacting Key Personnel 1. Getting knowledgeable people to locations is necessary for routine, emergency, and non-routine circumstances. 2. Important for the protection of personnel, equipment and to prevent radiological releases. 3. RCTs should be aware of communication equipment. G. Site Communication Systems (Insert site specific information here.) H. Emergency Communication Systems (Insert site specific information here.) III. SUMMARY A. Review major topics 1. Importance of communication 2. Methods of communication 3. Communication systems 4. FCC and DOE guidelines 5. General attributes of good communications 6. Contact of key personnel 7. Site communication systems 8. Site emergency communication B. Review learning objectives Objective 2.02.06 Objective 2.02.07 Objective 2.02.08 DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-5 IV. EVALUATION Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% should be the minimum passing criteria for examinations. DOE-HDBK-1122-2009 Module 2.02 Communication Systems Instructor’s Guide 2.02-6 This page intentionally left blank. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Course Title: Radiological Control Technician Module Title: Counting Errors and Statistics Module Number: 2.03 Objectives: (This document, Instructor's Material, is referred to as Instructor's Guide in the Program Management Guide) 2.03.01. Identify five general types of errors that can occur when analyzing radioactive samples, and describe the effect of each source of error on sample measurements. 2.03.02. State two applications of counting statistics in sample analysis. 2.03.03. Define the following terms: a. mode b. median c. mean 2.03.04. Given a series of data, determine the mode, median, or mean. 2.03.05. Define the following terms: a. variance b. standard deviation 2.03.06. Given the formula and a set of data, calculate the standard deviation. 2.03.07. State the purpose of a Chi-squared test. → 2.03.08. State the criteria for acceptable Chi-squared values at your site. 2.03.09. State the purpose of creating quality control (QC) charts. → 2.03.10. State the requirements for maintenance and review of QC charts at your site. 2.03.11. State the purpose of calculating warning and control limits.

2.03.12. State the purpose of determining efficiencies and correction factors. 2.03.13. Given counting data and source assay information, calculate efficiencies and correction factors. 2.03.14. State the meaning of counting data reported as x ± y. 2.03.15. Given counting results and appropriate formulas, report results to desired confidence level. 2.03.16. State the purpose of determining background. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material → 2.03.17. State the method and requirements for determining background for counting systems at your site. 2.03.18. State the purpose of performing sample planchet maintenance. → 2.03.19. State the method and requirements for performing planchet maintenance for counting systems at your site. 2.03.20. Explain methods to improve the statistical validity of sample measurements. 2.03.21. Define "detection limit," and explain the purpose of using detection limits in the analysis of radioactive samples. → 2.03.22. Given the formula and necessary information, calculate detection limit values for counting systems at your site. 2.03.23. State the purpose and method of determining crosstalk. → 2.03.24. State the criteria for acceptable values of crosstalk for counting systems at your site. 2.03.25. State the purpose of performing a voltage plateau. → 2.03.26. State the method of performing a voltage plateau on counting systems at your site. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material References: 1. "Advanced Health Physics Course Prestudy Guide," United States Nuclear Regulatory Commission, General Physics Corporation, 1987. 2. Chase & Rabinowitz, "Principles of Radioisotope Methodology," 3rd Edition, Burgess Publishing, 1987. 3. Gollnick, Daniel A., "Basic Radiation Protection Technology," 6th Edition, Pacific Radiation Corporation, Altadena, CA, 2012. 4. Knoll, Glenn F., "Radiation Detection and Measurement," 4th Edition, John Wiley & Sons, New York, 2010. 5. "Webster's New World Dictionary," 4thd College Edition, Webster's New World, Cleveland & New York, 2003. 6. Moe, Harold, "Operational Health Physics Training," ANL-88-26; DOE; Argonne National Laboratory, Chicago, 1988. 7. "Introduction to Low-background Counting Systems," Oxford-Tennelec Instruments. 8. Environmental Implementation Guide for Radiological Survey Procedures--Draft; DOE; February 1997. 9. Accuracy and Detection Limits for Bioassay Measurements in Radiation Protection - Statistical Considerations; U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research; April 1986. 10. “Manual for Conducting Radiological Surveys in Support of License Termination – Draft Report for Comment,” NUREG/CR-5849/ORAU-92/C57, June 1992. 11. “Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM),” NUREG-1575, Rev. 1 / EPA 402-R-97-016, Rev. 1 / DOE/EH-0624, Rev. 1, August 2000. 12. Multi-Agency Radiation Survey and Assessment of Materials and Equipment Manual (MARSAME) (NUREG-1575, Supplement 1), January 2009. Instructional Aids: 1 Chalkboard/whiteboard 2. Lessons learned DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material I. MODULE INTRODUCTION A. Self-Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation

Radiological sample analysis involves observation of a random process, one that may or may not occur, and estimation of the amount of radioactive material present based on that observation. All over the country radiological control personnel are using the activity measurements to make decisions that may affect the health and safety of workers at those facilities and their surrounding environments. C. Overview of Lesson 1. This unit will present an overview of measurement processes, and statistical evaluation of both measurements and equipment performance. 2. In addition, this unit will address some of the actions to take to minimize the sources of error in count room operations. D. Introduce Objectives II. MODULE OUTLINE 2.03.01 Identify five general types of errors that can occur when analyzing radioactive samples, and describe the effect of each source of error on sample measurements. GENERAL SOURCES OF ERROR Assuming the counting system is calibrated correctly, there are five general sources of error associated with counting a sample: 1. Self-absorption 2. Backscatter 3. Resolving time 4. Geometry 5. Random disintegration of radioactive atoms (statistical variations). DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Self-Absorption When a sample has an abnormally large amount of material on the sample media (or the sample itself is large), it could introduce a counting error due to self-absorption, which is the absorption of the emitted radiation by the sample material itself. Self-absorption could occur for: • Liquid samples with a high solid content • Air samples from a high dust area • Use of improper filter paper may introduce a type of self-absorption, especially in alpha counting (i.e., absorption by the media, or filter). Personnel counting samples should ensure the correct sample media is used, and that the sample does not become too heavily loaded with sample material. Count room personnel should be routinely checking samples for improper media or heavily loaded samples. Backscatter Counting errors due to backscatter occur when the emitted radiation traveling away from the detector is reflected, or scattered back, to the detector by the material in back of the sample. The amount of radiation that is scattered back will depend upon the type and energy of the radiation and the type of backing material (reflector). The amount of backscattered radiation increases as the energy of the radiation increases and as the atomic number of the backing material increases. Generally, backscatter error is only a consideration for particulate radiation, such as alpha and beta particles. Because beta particles are more penetrating than alpha particles, backscatter error will be more pronounced for beta radiation. The ratio of measured activity of a beta source counted with a reflector compared to counting the same source without a reflector is called the backscatter factor (BF). counts − with − reflector (Equation 1) BF = counts − without − reflector Normally, backscatter error is accounted for in the efficiency or conversion factor of the instrument. However, if different reflector materials, such as aluminum and stainless steel, are used in calibration and operation, an additional unaccounted error is introduced. (This additional error will be about 6% for stainless steel versus aluminum.) Count room

personnel must be aware of the reflector material used during calibration of the counting equipment. Any deviation from that reflector material will introduce an unaccounted error and reduce confidence in the analysis results. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Resolving Time Resolving time (or dead time) is the time interval which must elapse after a detector pulse is counted before another pulse can be counted. Any radiation entering the detector during the resolving time will not be recorded as a pulse; therefore, the information on that radiation interaction is lost. As the activity, or decay rate, of the sample increases, the amount of information lost during the resolving time of the detector is increased. As the losses from resolving time increase, an additional error in the measurement is introduced. Typical resolving time losses are shown in Table 1. Instructor's note: The total time required for GM tube to give maximum pulse height pulses is Recovery time. Table 1. Typical Resolving Time Losses Count rate (cpm) GM Tube 1 Proportional 2 Scintillation 3 20,000 1.7% < 1% < 1% 40,000 3.3% < 1% < 1% 60,000 5.0% < 1% < 1% 100,000 8.3% < 1% 1.0% 300,000 25.0% < 1% 3.5% 500,000 42.0% 1.5% 5.8% 1 GM tube: 50µs resolving time 2 Proportional detector: 2µs resolving time 3 Scintillation detector: 7µs resolving time DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Resolving time losses can be corrected by using the equation: R (Equation 2) R = o 1− R τ o where: R = "true" count rate, in cpm Ro = observed count rate, in cpm τ = resolving time of the detector, in minutes ("tau") Count room personnel should be aware of the limitations for sample count rate, based upon procedures and the type of detector in use, to prevent the introduction of additional resolving time losses. This is especially true for counting equipment that uses GM detectors. Instructor note: A detector, or detection system, can be characterized by a paralyzable or non­ paralyzable behaviour. In a non-paralyzable detector, an event happening during the dead time since the previous event is simply lost, so that with an increasing event rate the detector will reach a saturation rate equal to the inverse of the dead time. In a paralyzable detector, an event happening during the dead time since the previous one will not just be missed, but will restart the dead time, so that with increasing rate the detector will reach a saturation point where it will be incapable of recording any event at all. A semi-paralyzable detector exhibits an intermediate behaviour, in which the event arriving during dead time does extend it, but not by the full amount, resulting in a detection rate that decreases when the event rate approaches saturation. Geometry Geometry related counting errors result from the positioning of the sample in relation to the detector. Normally, only a fraction of the radiation emitted by a sample is emitted in the direction of the detector because the detector does not surround the sample. If the distance between the sample and the detector is varied, then the fraction of emitted radiation which hits the detector will change. This fraction will also change if the orientation of the sample under the detector (i.e., side-to-side) is varied. An error in the measurement can be introduced if the geometry of the sample and

detector is varied from the geometry used during instrument calibration. This is especially critical for alpha counting, where any change in the sample-to-detector distance also increases (or decreases) the chance of attenuation of the alpha particles by the air between the sample and detector. Common sources examples of geometry-related errors include: DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material • Piling smears and/or filters on top of each other in the same sample holder (moves the top sample closer to the detector and varies the calibration geometry). • Using deeper or shallower sample holders than those used during calibration (changes the sample-to-detector distance). • Adjusting movable bases in the counting equipment sliding drawer (changes the sample-to-detector distance). • Using too many or inappropriate sample holders or planchets (changes the sample-to-detector distance). Sources not fixed in position can change geometry and reduce reproducibility. • Plexiglass shelving in counting chamber is improperly set. Random Disintegration The fifth source of general counting error is the random disintegration of the radioactive atoms and constitutes the remainder of the lesson. STATISTICS Statistics is a branch of mathematics that deals with the organization, analysis, collection, and interpretation of statistical data. No definition of statistical data is given. However, Webster's does define a statistic as "an estimate of a variable, as an average or a mean, made on the basis of a sample taken from a larger set of data." This last definition is applicable to our discussion of counting statistics. After all, when we take samples, we use the data derived from analysis of those samples to make determinations about conditions in an area, in water, in air, etc., assuming that the sample is representative. So, we have estimated conditions (a variable) on the basis of a sample (our smear, water sample, air sample) taken from a larger set of data. Over the years, various methods and observations have identified three models which can be applied to observations of events that have two possible outcomes (binary processes). Luckily, we can define most observations in terms of two possible outcomes. For example, look at the following table: DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Table 2: Probability of Success Trial Definition of Success Probability of Success Tossing a coin Rolling a die observing a given radioactive nucleus for a time, t "heads" "a six" The nucleus decays during the observation 1/2 1/6 1-e -λt For each of the processes that we want to study, we have defined a trial (our test), a success and a failure (two possible outcomes), and have determined the probability of observing our defined success. Now, to study these processes, we can use proven, statistical models to evaluate our observations for error. Consider the possibilities when throwing two dice. There are 36 possible outcomes when throwing two dice, as indicated in Table 3. Table 3. Possibilities in Rolling Dice Result Possibilities No. of Possibilities 2 1&1 1 3 1&2,2&1 2 4 1&3,2&2,3&1 3 5 1&4,2&3,4&1,3&2 4 6 1&5,2&4,3&3,4&2,5&1 5 7 1&6,2&5,3&4,4&3,5&2,6&1 6 8 2&6,3&5,4&4,5&3,6&2 5 9 3&6,4&5,5&4,6&3 4 10 4&6,5&5,6&4 3 11 5&6,6&5 2 12 6&6 1

If, in our study of this process, we define a success as throwing a number between 2 and 12, the outcome is academic. All trials will be successful, and we can describe the probabilities of throwing any individual number between the range of 2 and 12 inclusive would add up to 1. If we define a success as throwing a particular number, we can define the probability of our success in terms of the number of possible outcomes that would give us that number in comparison to the total number of possible outcomes. If we were to take two dice, roll the dice a large number of times, and graph the results in the same manner, we would expect these results to produce a curve such as the one shown in Figure 1. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material The area under the curve can be mathematically determined and would correspond to the probability of success of a particular outcome. For example, to determine the probability of throwing a particular number between 2 and 12 we would calculate the area under the curve between 2 and 12. The results of that calculation is 36. This is what statistics is all about; random binomial processes that should produce results in certain patterns that have been proven over the years. The three models that are used are distribution functions of binomial processes with different governing parameters. These functions and their restrictions are: • Binomial Distribution This is the most general of the statistical models and is widely applicable to all processes with a constant probability. It is not widely used in nuclear applications because the mathematics are too complex. • Poisson Distribution A simplified version of binomial distribution is the Poisson (pronounced "pwusówn") distribution, which is valid when the probability of success, P(x), is small. If we graphed a Poisson distribution function, we would expect to see the predicted number of successes at the lower end of the curve, with successes over the entire range if sufficient trials were attempted. Thus, the curve would appear as seen in Figure 2. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material The Poisson model is used mainly for applications involving counting system background and detection limits, where the population (i.e., number of counts) is small. This will be discussed in greater detail later. • Gaussian Distribution Also called the "normal distribution," the Gaussian (pronounced "Gowziun") distribution is a further simplification which is applicable if the average number of successes is relatively large, but the probability of success is still low. A graph of a Gaussian distribution function is shown in Figure 3. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Note that the highest number of successes is at the center of the curve, the curve is a bell shaped curve, and the relative change in success from one point to the adjacent is small. Also note that the mean, or average number of successes, is at the highest point, or at the center of the curve. The Gaussian, or normal, distribution is applied to counting applications where the mean count or success is expected to be greater than 20. It is used for counting system calibrations and operational checks, as well as for normal samples containing activity. It

may or may not include environmental samples (i.e., samples with very low activity). 2.03.02 State the two purposes for statistical analysis of count room operations. APPLICATION OF STATISTICAL MODELS Application of specific statistical methods and models to nuclear counting operations is termed counting statistics and is essentially used to do two things: • Predict the inherent statistical uncertainty associated with a single measurement, thus allowing us to estimate the precision associated with that measurement. • Serve as a check on the normal function of nuclear counting equipment. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material 2.03.03 Define the following terms: a. mode b. median c. mean DEFINITIONS Mode An individual data point that is repeated the most in a particular data set. Median The center value in a data set arranged in ascending order. Mean The average value of all the values in a data set. 2.03.04 Given a series of data, calculate mode, median, or mean. DETERMINATION OF MODE, MEDIAN, AND MEAN • Determination of the Mode: In the set of test scores above, a score of 95 occurs (i.e., is repeated) more often than any other score. • Determination of the Median: In the same set of test scores, this is the score in the middle - where one half of the scores are below, and the other half are above the median. The median for the test scores in Figure 4 is 90. • Determination of the Mean: This is found by adding all of the values in the set together, and dividing by the number of values in the set. The mean of the nine test scores is 89. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Mean determination is often expressed using special symbols, as illustrated in the following equation: Σx (Equation 3) x = i n 2.03.05 Define the following terms: a. variance b. standard deviation 2.03.06 Given the formula and a set of data calculate the standard deviation. VARIANCE AND STANDARD DEVIATION Using the Gaussian distribution model depicted in Figure 5 (below) we need to define the terms "variance" and "standard deviation," which are both used as descriptors of the spread of the population (or the data set) in a normal distribution. E Statistics f data points around the mean , it tells how much the data "varies" from the mean. al distribution, the standard deviation is recise than the variance is The standard deviation of a sample is defined mathematically are located close to the mean, the curve will be tall and steep value for a standard ot as steep and have a larger numerical value for a standard , it has been determined mathematically that 68.2% of the area in the data point located at the mean ± (plus or minus) one 95.4% of the area under the curve falls between the data point deviations (2 ated at ± processes is that if the distribution (as depicted in Figure 5) is ng function with a mean observable success >20 (Gaussian the observed successes (or counts) will be within ±1 standard ean. the observed successes (or counts) will be within ±2 standard ean. D Counting Errors an ctor’s amount of scatter e sample . In other word an. Mathematically, in a nor uare root . A term more epresented by a (pronounced “sigma”). athematically = If most of the data points tall and steep and have a low numerica re scattered, the curve will be lower and r a standard

In a Gaussian distributio .2% of the area it inus) one ) the data point two standard curve falls point lo hat this means to us in terms of countin in Figure 5) is representative of a count (Gaussian 68.2% of the tim in ±1 standard deviation of the 95.4% of the tim in ±2 standard deviations of the Instr is defined as t . In other words, it tells how much the data "varies" from the m the s , (pronounced “sigma”). The standard deviation of a sample is defined If most of the data points are located close to the mean, the curve will be deviation. If data points curve will be lower and not as steep and have a larger numerical value f In a Gaussian distribution, it has been determined mathematically that 6 ithin the data point located at the mean ± (plus or ); 95.4% of the area under the curve falls betwee ), 99.97% of the area under the ) etc. to us in terms of counting processes is that if the distribution (as depicte representative of a counting function with a mean observable success >2 68.2% of the time the observed successes (or counts) will be wit 95.4% of the time the observed successes (or counts) will be wit DO OE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and d Statistics Instru uctor’s Material Variance The amount of scatter o of data points around the mean is defined as th he sample variance. In other words s, it tells how much the data "varies" from the me ean. Standard Deviation Mathematically, in a norm mal distribution, the standard deviation is the sq quare root of the variance. A term more p precise than the variance is standard deviation, r represented by a σ (pronounced “sigma”). The standard deviation of a sample is defined m mathematically as: (Equation 4) σ = √(∑(xi ­ ) 2 / (n - 1)) where: σ = standard deviation of a sample xi = sample counts for each data point = mean n = number of data points If most of the data points are located close to the mean, the curve will be tall and steep and have a low numericall value for a standard deviation. If data points a are scattered, the curve will be lower and n not as steep and have a larger numerical value fo or a standard deviation. In a Gaussian distribution n, it has been determined mathematically that 68 8.2% of the area under the curve falls with hin the data point located at the mean ± (plus or mminus) one standard deviation (1 σ ); ; 95.4% of the area under the curve falls between n the data point located at ± two standard deviations (2 σ ), 99.97% of the area under the curve falls between the data point loccated at ± three standard deviations (3 σ ) etc. WWhat this means to us in terms of counting g processes is that if the distribution (as depicted d in Figure 5) is representative of a counti ing function with a mean observable success >200 (Gaussian distribution): • 68.2% of the time e the observed successes (or counts) will be with hin ±1 standard deviation of the m mean. • 95.4% of the time e the observed successes (or counts) will be with hin ±2 standard deviations of the m mean. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material • 99.97% of the time the observed successes (or counts) will be within ±3 standard deviations of the mean. Remember, the area of the curve represents the probability of success in a random process. In radiation protection this random process is the decay of a radioactive sample.

The known statistical distribution is used in radiation protection when setting up a counting system and in evaluating its operation by means of daily pre-operational source checks. In performing the calibration of the system, a radioactive source with a known activity is counted twenty times for one minute each time. Using the data from the twenty counts, the mean and standard deviation can be calculated. The mean can then be used to determine the efficiency of the system while allowing for a certain number of standard deviations during operation. The twenty counts can also be used to perform another required test of the system's performance, the chi-squared test (see below). Example 2.03-1 Calculate the mean and sample standard deviation for the following data set: 193, 188, 202, 185, 179, 217, 191 199, 201, 214, 193, 232, 199, 210, 196, 211, 191, 203, 201, 195 Instructor's Note: This module provides example problems for several of the topics. Instructors should add additional problems based on students' needs. 2.03.07 State the purpose of a Chi-squared test. CHI-SQUARED TEST The Chi-squared test (pronounced "ki") is used to determine the precision of a counting system. Precision is a measure of exactly how a result is determined without regard to its accuracy. It is a measure of the reproducibility of a result, or in other words, how often that result can be repeated, or how often a "success" can be obtained. This test results in a numerical value, called the Chi-squared value (X 2 ), which is then compared to a range of values for a specified number of observations or trials. This range represents the 2 expected (or predicted) probability for the chosen distribution. If the X value is lower than the expected range, this tells us that there is not a sufficient degree of randomness in the observed data. If the value is too high, it tells us that there is too much randomness in the observed data. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material The Chi-squared test is often referred to as a "goodness-of-fit" test. If it does NOT fit a curve indicating sufficient randomness, then the counting instrument may be malfunctioning. The Chi-squared value is calculated as follows: ∑ ( x − x) 2 i (Equation 5) X 2 = x Example 2.03-2 Using the data from Example 2.03-1, determine the Chi-squared value for the data set. 2.03.08 State the criteria for acceptable Chi-squared values at your site. (Insert site-specific information here.) Assuming a given set of data passes the Chi-squared test, the data can then be used to prepare quality control charts for use in verifying the consistent performance of the counting system. 2.03.09 State the purpose of creating quality control (QC) charts. 2.03.10 State the requirements for maintenance and review of QC charts at QUALITY CONTROL CHARTS Quality control charts may be prepared using source counting data obtained during system calibration. Obviously since this test verifies that the equipment is still operating within an expected range of response, we cannot change the conditions of the test in mid-stream. QC charts, then, enable us to track the performance of the system while in use. Data that can be used for quality control charts include gross counts, counts per unit time, and efficiency. Most nuclear laboratories use a set counting time corresponding to the normal counting time for the sample geometry being tested.

DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material When the system is calibrated and the initial calculations performed, the numerical values of the mean ± 1, 2, and 3 standard deviations are also determined. Using graph paper or a computer graphing software, lines are drawn all the way across the paper at those points corresponding to the mean, the mean plus 1, 2, and 3 standard deviations, and the mean minus 1, 2, and 3 standard deviations. The daily control check results are then plotted on the control chart to see if the results fall outside the limits (Insert site-specific information here.) 2.03.11 State the purpose of calculating warning and control limits. SYSTEM OPERATING LIMITS The values corresponding to ±2 and ±3 standard deviations may be called the upper and lower warning and control limits, respectively (or other terms such as action limits) . The results of the daily source counts are graphed in many countrooms. Most of the time results will lie between the lines corresponding to ±1 standard deviation (68.2%). We also know that 95.4% of the time our count will be between ±2 standard deviations and that 99.97% of the time our count will be between ±3 standard deviations. Counts that fall outside the warning limit (±2 σ ) are not necessarily incorrect. Statistical distribution models say that we should get some counts in that area. Counts outside the warning limits indicate that something MAY be wrong. The same models say that we will also get some outside the control limits (±3 σ ). However, not very many measurements will be outside those limits. We use 3 σ as the control – a standard for acceptable performance. In doing so we say that values outside of ±3 σ indicate unacceptable performance, even though those values may be statistically valid. True randomness also requires that there be no patterns in the data that are obtained; some will be higher than the mean, some will be lower, and some will be right on the mean. When patterns do show up in quality control charts, they are usually indicators of systematic error. For example: • Multiple points outside two sigma • Repetitive points (n out of n) outside one sigma • Multiple points, in a row, on the same side of the mean DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material • Multiple points, in a row, going up or down. The assumption is made that systematic error is present in our measurements, and that our statistical analysis has some potential for identifying its presence. However, industry assumption is that systematic error that is present is very small in comparison to random error. Quality control charts should be maintained in the area of the radioactivity counting system such that they will be readily accessible to those who operate the system. These charts can then be used by operators to determine if routine, periodic checks (typically daily) have been completed before system use. 2.03.12 State the purpose of determining efficiencies and correction factors. 2.03.13 Given counting data and source assay information, calculate efficiencies and correction factors. COUNTER EFFICIENCY A detector intercepts and registers only a fraction of the total number of radiations emitted by a radioactive source. The major factors determining the fraction of radiations emitted by a source that are detected include:

• The fraction of radiations emitted by the source which travel in the direction of the detector window • The fraction emitted in the direction of the detector window which actually reach the window • The fraction of radiations incident on the window which actually pass through the window and produce an interaction • The fraction scattered into the detector window All radiation detectors will, in principle, produce an output pulse for each particle or photon which interacts within its active volume. Because of the factors outlined above, only a fraction of the disintegrations occurring in a source result in counts being reported by the detector. Therefore, there is only a certain fraction of the disintegrations occurring that results in counts reported by the detector. Using a calibrated source with a known activity, a precise figure can be determined for this fraction. This value can then be used as a ratio in order to relate the number of pulses counted to the number of particles and/or photons emitted by the source. This ratio is called the efficiency. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material The detector efficiency gives us the fraction of counts detected per disintegration, or c/d. Since activity is the number of disintegrations per unit time, and the number of counts are detected in a finite time, the two rates can be used to determine the efficiency if both rates are in the same units of time. Counts per minute (cpm) and disintegrations per minute (dpm) are the most common. Thus, the efficiency, E, can be determined as shown in Equation 6. Used in this manner the time units will cancel, resulting in counts/disintegration (c/d). cpm c (Equation 6) E = = dpm d The efficiency obtained in the formula above will be in fractional or decimal form. To calculate the percent efficiency, the fraction can be multiplied by 100. For example, an efficiency of 0.25 would mean 0.25 × 100, or 25%. Example 2.03-3 A source is counted and yields 2840 counts per minute. If the source activity is known to be 12,500 dpm calculate the efficiency and percent efficiency. By algebraic manipulation, Equation 6 can be solved for the disintegration rate (see Equation 7). The system efficiency is determined as part of the calibration. When analyzing samples, a count rate is reported by the counting system. Using Equation 7, the activity, (A), of the sample can be determined in dpm, and then converted to any other units of activity (e.g., Ci, Bq). cpm cpm (Equation 7) dpm = E ⎯⎯→ dpm A = E Example 2.03-4 A sample is counted on a system with a 30% efficiency. If the detector reports 4325 net counts per minute what is the activity of the sample in dpm? A correction factor (CF), which is simply the inverse of the efficiency, is used by multiplying it by the net count rate to determine the activity, as in Equation 8. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material 1 (Equation 7) CF = E Example 2.03-5 An instrument has an efficiency of 18%. What is the correction factor? This count-rate correction factor should not be confused with a geometry correction factor used with some radiation instruments, such as the beta correction factor for a Cutie Pie (RO-3C). 2.03.14 State the meaning of counting data reported as x.xx ± yy. 2.03.15 Given counting results and appropriate formulas, report results to desired

confidence level. ERROR CALCULATIONS The error present in a measurement governed by a statistical model can be calculated using known parameters of that model. Nuclear laboratories are expected to operate at a high degree of precision and accuracy. However, since we know that there is some error in our measurements, we are tasked with reporting measurements to outside agencies in a format that identifies that potential error. The format that is used should specify the activity units and a range in which the number must fall. In other words, the results would be reported as a given activity plus or minus the error in the measurement. Since nuclear laboratories prefer to be right more than they are wrong, counting results are usually reported in a range that would be correct 95% of the time, or at a 95% confidence level. In order to do this, the reported result should be in the format: (Equation 9) x.xx ± yy (K σ ) where: x.xx = measured activity, in units of dpm, Ci, or Bq yy = associated potential (or possible) error in the measurement K = multiple of counting error σ = standard deviation at stated confidence level (CL) DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Note: Use of K σ is only required for confidence levels other than 68% (see Table 4). Therefore: σ = 1× σ 68% CL (optional) 1.64 σ = 1.64 × σ 90% CL (sometimes used) 2 σ = 1.96 × σ 95% CL (normally used) For example, a measurement of 150 ± 34 dpm (2 σ ) indicates the activity as 150 dpm; however, it could be as little as 116 dpm or as much as 184 dpm with 95% confidence (at 2 σ ). The calculations of the actual range of error is based on the standard deviation for the distribution. In the normal (or Gaussian) distribution, the standard deviation of a single count is defined as the square root of the mean, or σ = x . The error, e, present in a single count is some multiplier, K, multiplied by the square root of that mean, i.e., some multiple times the standard deviation, K σ . The value of K used is based on the confidence level that is desired, and is derived from the area of the curve included at that confidence level (see Figure 5). Common values for K include: Table 4. Counting Error Multiples Error Confidence Level K Probable 50% 0.6745 Standard 68% 1.0000 9/10 90% 1.6449 95/100 95% 1.9600 99/100 99% 2.5750 To calculate the range to the point at which you would expect to be right 95% of the time, you would multiply the standard deviation by 1.96, and report the results of the measurement as x.xx dpm ± yy dpm (2 σ ). Note that using a 68% or 50% confidence level introduces an expected error a large percentage of the time. Therefore, for reasonable accuracy a higher confidence level must be used. The simple standard deviation (σ) of the single count (x) is usually determined as a count rate (counts per unit time). This is done by dividing the count rate (R) by the count time (T). Subscripts can be applied to distinguish sample count rates from background count rates. (Equation 10) σ = K R T DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Example 2.03-6 The count rate for a sample was 250 cpm. Assume 10 minute counting time, zero background counts and a 25% efficiency. Report sample activity at a 95% C.L. 2.03.16 State the purpose of determining background. BACKGROUND Determination of Background

Radioactivity measurements cannot be made without consideration of the background. Background, or background radiation, is the radiation that enters the detector concurrently with the radiation emitted from the sample being analyzed. This radiation can be from natural sources, either external to the detector (i.e., cosmic or terrestrial) or radiation originating inside the detector chamber that is not part of the sample. In practice, the total counts are recorded by the counter. This total includes the counts contributed by both the sample and the background. Therefore, the contribution of the background will produce an error in radioactivity measurements unless the background count rate is determined by a separate operation and subtracted from the total activity, or gross count rate. The difference between the gross and the background rates is called the net count rate (sometimes given units of ccpm, or corrected counts per minute). This relationship is seen in the following equation: (Equation 11) RS = R B − RS + B where: RS = net sample count rate (cpm) RS+B = gross sample count rate (cpm) RB = background count rate (cpm) The background is determined as part of the system calibration by counting a background (empty) sample holder for a given time. The background count rate is determined in the same way as any count rate, where the gross counts are divided by the count time, as seen in Equation 12 below. N B(Equation 12) R B = TB DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material where: RB = background count rate (counts per time, i.e., cpm) NB = gross counts, background TB = background count time In practice, background values should be kept as low as possible. As a guideline, background on automatic counting systems should not be allowed to exceed 0.5 cpm alpha and 1 cpm beta-gamma. If system background is above this limit the detector should be cleaned or replaced. Reducing Background Typically, the lower the system background the more reliable the analysis of samples will be. In low-background counting systems the detector housing is surrounded by lead shielding so as to reduce the background. Nonetheless, some background still manages to reach the detector. Obviously, little can be done to reduce the actual source of background due to natural sources. On many systems a second detector is incorporated to detect penetrating background radiation. When a sample is analyzed the counts detected by this second detector during the same time period are internally subtracted from the gross counts for the sample. Background originating inside the detector chamber can be, for the most part, more easily controlled. The main contributors of this type of background are: • Radiation emitted from detector materials • Radioactive material on inside detector surfaces • Radioactive material on the sample slide assembly • Contamination in or on the sample planchet or planchet carrier There are, unfortunately, trace levels of radioactivity in the materials of which detectors and their housings are made. This is simply a fact of life in the atomic age. The contribution to background from such materials is negligible, but should nonetheless be acknowledged. Radioactive material can be transferred from contaminated samples to the inside surfaces of the detector chamber during counting. This usually occurs when samples having gross

amounts of material on them are counted in a lowbackground system. During the insertion and withdrawal of the sample into the detector chamber, loose material can be spread into the chamber. In order to prevent this, these samples should be counted using a field survey instrument or a mini-scaler. Low-background systems are designed for counting lower-activity samples. Counting of a high-activity sample on these systems should be avoided unless it is a sealed radioactive source. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material (Insert site-specific information here.) Note: The following is provided as an example as a typical counting system. Radioactive material can also be transferred from contaminated samples to the slide assembly upon which samples are inserted into, and withdrawn from, the detector chamber. This can be prevented in the same way as stated above. In addition, when loading and stacking samples for counting, ensure that the slide assembly cover is in place. The slide assembly should also be cleaned on a routine basis (i.e., weekly). When loading and unloading samples into and from planchets, material from the samples can be spread to the planchet and/or the carrier. Most smears and air samples are 47-mm diameter and are counted in a planchet that is almost the same size. The planchet is placed in a carrier which surrounds and supports the planchet and allows for automatic sample exchange by the counting system. When a sample is counted, the entire carrier is placed under the detector window inside the detector chamber. Any contamination on the carrier (or in the planchet) is counted with, and attributed to, the sample. A paper disc can be placed in the bottom of the planchet as a step in preventing transfer of material from samples to the planchet. Care should be taken when loading and unloading samples such that material remains on the sample media. 2.03.17 State the method and requirements for determining background for counting systems at your site. (Insert site-specific information here.) 2.03.18 State the purpose of performing planchet maintenance. PLANCHET MAINTENANCE Planchets and carriers should be inspected, cleaned, and counted on a routine basis. All in-use planchets and carriers must read less than established site limits. Planchets exceeding these limits should be decontaminated and recounted as necessary. By maintaining planchets clean and as free from contamination as possible, sample result reliability will be increased because the amount of error introduced in the sample analysis will be reduced. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material 2.03.19 State the method and requirements for performing planchet maintenance for counting systems at your site. PROPAGATION OF ERROR The error present in a measurement includes the error present in the sample count and the error present in the background count. The total error in the measurement is calculated by squaring the error in the background and adding that to the square of the error in the sample count, and taking the square root of the sum, as shown in Equation 13. (Equation 13) e = e 2 + e 2 S S + B B where: eS = error present in the measurement (sample) eS+B = error in sample count (sample plus background) eB = error present in background count Since we normally use this equation in terms of a count rate, the formula is slightly modified as

follows, and the error stated as the sample standard deviation (σ S): R RS +B B(Equation 14) Kσ S = K + TS TB where: RS+B = gross sample count rate (sample plus background) RB = background count rate TS = sample count time TB = background count time K = confidence level multiple (see Table 4) The error in the sample count is the standard deviation of the count, which is the square root of that count (see Equation 13 above). Example 2.03-7 An air sample is counted and yields 3500 counts for a 2-minute count period. The system background is 10 cpm determined over a 50-minute count time. Determine the error in the sample and report the net count rate to 95% confidence level. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material If the sample counting time and the background counting time is the same, the formula can be simplified even more to: R + RS +B B(Equation 15) Kσ = K s T Example 2.03-8 A long-lived sample is counted for one minute and gives a total of 562 counts. A one minute background gives 62 counts. Report net sample count rate to 95% CL. 2.03.20 Explain the methods used to improve the statistical validity of count room measurements. IMPROVING STATISTICAL VALIDITY OF COUNT ROOM MEASUREMENTS Minimizing the statistical error present in a single sample count is limited to several options. If we look at the factors present in the calculation below (same as Equation 14), we can see that there are varying degrees of control over these factors. The standard deviation is calculated here in terms of count rate. R RS +B Bσ rate = + TS TB RS+B is the sample count rate. We really have no control over this. RB is the background count rate. We do have some control over this. On any counting equipment the background should be maintained as low as possible. In most of our counting applications, however, the relative magnitude of the background count rate should be extremely small in comparison to the sample count rate if proper procedures are followed. This really becomes an issue when counting samples for free release or environmental samples. However, some reduction in error can be obtained by increasing the background counting time, as discussed below. TB and TS are the background and sample counting times, respectively. These are the factors that we have absolute control over. In the previous section we talked about the reliability of the count itself. We have been able to state that a count under given circumstances may be reproduced with a certain confidence level, and that the larger the number of counts the greater the reliability. The condition we have been assuming is that our count is taken within a given time. In order to get more precise results, many counts must be observed. Therefore, if we have DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material low count rates, the counting time must be increased in order to obtain many counts, thereby making the result more precise (or reproducible). The total counting time required depends upon both the sample and background count rates. For high sample activities the sample count time can be relatively short compared to the background count time. For medium count rates we must increase the sample count time in order to increase precision. As the sample activity gets even lower, we approach the case where we must devote

equal time to the background and source counts. In other words, by counting low activity samples for the same amount of time as that of the background, we increase the precision of our sample result. However, we must never count a sample for a period of time longer than the system background. In summary, by minimizing the potential error present, we improve statistical validity of our measurements. 2.03.21 Define "detection limit," and explain the purpose of using detection limits in the analysis of radioactive samples. DETECTION LIMITS The detection limit of a measurement system refers to the statistically determined quantity of radioactive material (or radiation) that can be measured (or detected) at a preselected confidence level. This limit is a factor of both the instrumentation and technique/procedure being used. The two parameters of interest for a detector system with a background response greater than zero are (see Figure 6): LC Critical detection level: the response level at which the detector output can be considered "above background" LD Minimum significant activity level, i.e., the activity level that can be seen with a detector with a fixed level of certainty These detection levels can be calculated by the use of Poisson statistics, assuming random errors and systematic errors are separately accounted for, and that there is a background response. For these calculations, two types of statistical counting errors must be considered quantitatively in order to define acceptable probabilities for each type of error: Type I - occurs when a detector response is considered above background when in fact it is not (associated with LC) Type II - occurs when a detector response is considered to be background when in fact it is greater than background (associated with LD) 2.71 DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material If the two probabilities (areas labeled I and II in Figure 6) are assumed to be equal, and the background of the counting system is not well-known, then the critical detection level (LC) and the minimum significant activity level (LD) can be calculated. The two values would be derived using the equations LC = kσB and LD = k 2 + 2kσB, respectively. If 5% false positives (Type I error) and 5% false negatives (Type II error) are selected to be acceptable levels, i.e., 95% confidence level, then k = 1.645 and the two equations can be written as: RB RB(Equation 16) LC = 1.645 + TB TS R R3 B B(Equation 17) LD = + 3.29 + TS TB TS where: LC = Critical detection level LD = a priori detection limit [minimum significant activity level RB = background count rate TB = background count time TS = sample count time 2.71 DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material The minimum significant activity level, LD, is the a priori (before the fact) activity level that an instrument can be expected to detect 95% of the time. In other words, it is the smallest amount of activity that can be detected at a 95% confidence level. When stating the detection capability of an instrument, this value should be used. The critical detection level, LC, is the lower bound on the 95% detection interval defined for LD, and is the level at which there is a 5% chance of calling a background value "greater than background." This value (LC) should be used when actually counting samples or making direct

radiation measurements. Any response above this level should be counted as positive and reported as valid data. This will ensure 95% detection capability for LD. If the sample count time (TS) is the same as the background count time (TB), then equations 16 and 17 can be simplified as follows: (Equation 18) LC = 2.32 RB T R (Equation 19) LD = 3 + 4.65 B T T where: T = count time (sample and background) Therefore, the full equations for LC and LD must be used for samples with count times differing from the background determination time (95% CL used). These equations assume that the standard deviation of the sample planchet/carrier background during the sample count (the planchet/carrier assumed to be 0 activity) is equal to the standard deviation of the system background (determined using the background planchet/carrier). The critical detection level, LC, is used when reporting survey results. It is used to say that at a 95% confidence level, samples above this value are radioactive. This presupposes, then, that 5% of the time clean samples will be considered radioactive. The minimum significant activity level, LD, [also referred to as the LLD (Lower Limit of Detection) in some texts] is calculated prior to counting samples. This value is used to determine minimum count times based on release limits and airborne radioactivity levels. In using this value we are saying that at a 95% CL, samples counted for at least the minimum count time calculated using the LD that are positive will indeed be radioactive (above the LC). This presupposes, then, that 5% of the time samples considered clean will actually be radioactive. Example 2.03-9 A background planchet is counted for 50 minutes and yields 16 counts. Calculate the critical detection level and the minimum significant activity level for a 0.5 minute sample count time. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material 2.03.22 Given the formula and necessary information, calculate detection limit values for counting systems at your site. MINIMUM DETECTABLE ACTIVITY (MDA) The minimum significant activity level, LD , can be used to evaluate whether the measurement process is adequate to meet requirements. For example, the results of Example 2.03-9 (in units of cpm) can be converted using counting efficiency and area of swipe to determine the adequacy of the measurement system for contamination surveys for removable contamination performed to ensure that the removable surface contamination values specified in Appendix D of 10 CFR 835 are not exceeded (in units of dpm/100cm 2 ). In most cases, swipes to determine the removable contamination levels will be counted in the field or submitted to the counting lab for analysis where the background radiation levels are sufficiently low enough to ensure that LD, and thus MDA, are below the limits in 10 CFR 835 Appendix D. (Equation 19b) MDAremovable = LD x (100/Aswipe) / e where: MDAremovable = Activity level in dpm/100 cm 2 e = Detector efficiency in counts per disintegration Aswipe = Area of surface swiped in cm 2 Static Count MDAs Similarly, one can calculate a MDA for a static field measurement to evaluate total surface contamination values. In this case, an adjustment is needed to account for the size of the detector. To determine the MDA for static counts, i.e., the probe is stationary for a prescribed period of time, Equation 19c is used.

(Equation 19c) MDAtotal = LD x (100/Aprobe) / e where: MDAtotal = Activity level in dpm/100 cm 2 e = Detector efficiency in counts per disintegration Aprobe = Surface area of probe in cm 2 DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Scanning MDA The ability to identify a small region or area of slightly elevated radiation during surface scanning is dependent upon the RCT’s skill in recognizing an increase in the audible output of the instrument. Experience has shown that a 25% to 50% increase may be easily identifiable at ambient background levels of several thousand counts per minute, whereas, at ambient levels of a few counts per minute, a two to three fold increase in the audible signal is required before a change is readily recognizable. The detection sensitivity of scanning is dependent upon a number of other factors, such as detector scan speed, surface characteristics, size of elevated activity region, surveyor efficiency, level of activity, and detector/surface distance. The ability to detect an elevated region of activity using a particular survey scanning technique would need to be determined empirically and is beyond the scope of this training. Instructor's Note: If individuals will be involved in determining MDA's additional training such as MARSSIM or MARSAME should be considered. (Insert site-specific information here.) 2.03.23 State the purpose and method of determining crosstalk. CROSSTALK Discrimination Crosstalk is a phenomenon that occurs on proportional counting systems (such as a Tennelec) that employ electronic, pulse-height discrimination, thereby allowing the simultaneous analysis for alpha and beta-gamma activity. Discrimination is accomplished by establishing two thresholds, or windows, which can be set in accordance with the radiation energies of the nuclides of concern. Recall that the pulses generated by alpha radiation will be much larger than those generated by beta or gamma. This makes the discrimination between alpha and beta-gamma possible. Beta and gamma events are difficult to distinguish; hence, they are considered as one by such counting systems. In practice, the lower window is set such that electronic noise and ultra-low-energy photon events are filtered out. Any pulse generated whose size is greater than the setting for the lower window is considered an event, or a count. The upper window is then set such that any pulses which surpass the upper discriminator setting will be considered an alpha count (see Figure 7). DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material For output purposes, the system routes each count to a series of channels which simply keep a total of the counts routed to them. Channel A is for alpha counts, Channel B is beta-gamma counts, and Channel C is total counts. As a sample is being counted, all valid counts registered (i.e., those which surpass the lower discriminator setting) are routed to the C-channel. In addition, if the count was considered an alpha count (i.e., it surpassed the upper discriminator setting) it is routed to the A-channel; else it is tallied in the B-channel. In effect, what occurs is that the number of beta-gamma counts (Channel B) are determined by subtracting the number of alpha counts (Channel A) from the total counts (Channel C), or B = C - A. Origin of Crosstalk

Now that we understand the process involved, there is a dilemma that stems from the fact that events are identified by the system as either alpha or beta-gamma according to the size of the pulse generated inside the detector. The system cannot really tell what type of radiation has generated the pulse. Rather, the pulse is labeled as "alpha" or "beta­ gamma" by comparing the size of the pulse to the discriminator setting. It is the setting of the discriminator that poses the dilemma. Alpha particles entering the detector chamber generally are attenuated by the detector fill-gas because of their high LET, thereby producing a large pulse. Low-energy beta particles and photons will also lose all their energy within the detector gas, but DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material nevertheless produce a smaller pulse because of their lower energies. High energy beta particles can still retain some of their energy even after having produced a pulse while traversing the detector volume. Rather than leaving the detector, as would a photon, the beta is reflected off of the detector wall and reenters the volume of gas, causing ionizations and generating a second pulse. These two pulses can be so close together that the detector sees them as one large pulse. Because of the large pulse size it can surpass the upper discriminator setting and is, therefore, counted as an alpha, and not as a beta. The result is that alpha activity can be reported for a sample when in fact there was little or no alpha present. Conversely, if a true alpha-generated pulse is not large enough so as to exceed the upper discriminator, it would be counted as a beta-gamma event. This is crosstalk. The solution is not a simple one. The setting of the upper discriminator depends on the radiations and energies of the sources and samples being analyzed. If high energy beta radiations are involved, a significant portion of them could be counted as alpha events if the setting is too low. If the setting is too high, lower-energy alpha events could be counted as beta-gamma. Typically, the setting of the discriminator will usually be some "happy medium." A discussion of how this can be dealt with is in order. Calibration Sources and Crosstalk For calibrations of Tennelec counting systems, the manufacturer provides the following general recommendations for discriminator settings: First, using a Strontium-90 beta source, set the upper (A) discriminator such that there is 1% beta-to-alpha crosstalk. Then, using a Polonium-210 alpha source, set the A+B discriminator such that there is less than 3% alpha-to-beta crosstalk. Energies of sources used to calibrate counting systems should be the same as, or as close as possible to, the energies of radionuclides in the samples analyzed. Wherever possible they should be a pure emitter of the radiation of concern. For beta-gamma sources the most popular isotope in radiation protection is Sr-90. It has a relatively long half-life of 29.1 years, but emits betas of only 546 keV. However, Sr-90 decays to Yttrium-90, another beta emitter which has a short half-life of only 2.67 days and emits a 2.281 MeV beta. Y-90 decays to Zirconium-90m which emits a 2.186 Mev gamma almost instantaneously to become stable. The daughters reach equilibrium with the strontium parent within a number of hours after source assay. Hence, for every Sr

beta emitted a Y beta is also emitted, thereby doubling the activity. These sources are often listed as Sr/Y-90 for obvious reasons. This makes Sr/Y-90 sources an excellent choice and they are used by many sites for calibrations and performance testing. Po-210 is essentially a pure alpha emitter. This is primarily the reason why it is recommended for calibrations and performance testing. It yields a strong alpha, but it also has a short half-life. A comparison of some alpha emitters is given in Table 5. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Table 5. Alpha Emitters Isotope Half-Life Energy (MeV) Po-210 138.38 days 5.3044 Pu-239 2.4E4 years 5.156, 5.143, 5.105 Ra-226 1.60E3 years 4.78, 4.602 Th-230 7.54E4 years 4.688, 4.621 Natural U 4.4E9 years (avg.) 4.2 (avg.) 2.03.24 State the criteria for acceptable values of crosstalk for counting systems at your site (Insert site-specific information here.) VOLTAGE PLATEAUS Very simply put, a voltage plateau is a graph that indicates a detector's response to a specific energy particle with variations of high voltage. The x-axis represents the high voltage and the y-axis the response (i.e., counts). The resulting curve gives an indication of detector quality, and can indicate problems with the counting gas should they be present. The curve can also be used to determine the optimum operating high voltage for the system. Most automatic low-background counting systems provide several different analysis modes. These modes count samples at certain pre-determined voltages. Counting systems generally provide three analysis modes: • ALPHA ONLY • ALPHA THEN BETA • ALPHA AND BETA (SIMULTANEOUS) There are usually two voltage settings used in conjunction with these analysis modes: • Alpha voltage (lower) • [Alpha plus] Beta voltage (higher) DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material Recall that in a proportional counter the amount of voltage determines the amount of gas multiplication. Because of the high LET of alpha radiation, at a lower voltage, even though the gas amplification will be lower, alpha pulses will still surpass the lower discriminator and some will even pass the upper discriminator. Because of the lower gas amplification beta-gamma pulses will not be large enough to be seen. Therefore, any counts reported for the sample will be alpha counts. In the ALPHA ONLY mode, the sample is counted once, at the alpha voltage. Counts may appear in either the A or B channels. Upon output, the A and B channels will be added together and placed in Channel A and, therefore, reported as alpha counts; the B channel will be cleared to zero, thereby resulting in no beta-gamma counts. In the ALPHA THEN BETA mode, the sample is counted twice. The first count interval determines the alpha counts using the alpha voltage. The second count is done at the beta voltage. The determination of alpha and beta-gamma counts in this mode is based strictly on the operating characteristics of the detector at the different voltages. For this reason, the A and B counts are summed during both counting intervals to attain the total counts. The separation of alpha and beta-gamma counts is then calculated and reported according to the following formula: A +1 B1α = (Equation 20) CF α β = ( A2 − B2 ) − α where: α = reported gross alpha counts β = reported gross beta-gamma counts

A1,B1 = accumulated channel counts respectively, 1st interval A2,B2 = accumulated channel counts respectively, 2nd interval CFα = alpha correction factor (ratio of alpha efficiency at alpha voltage to efficiency at beta voltage) In the ALPHA AND BETA (SIMULTANEOUS) mode, the sample is counted once using the beta voltage. Alpha events are reported in the A channel, while beta-gamma counts are reported in the B channel. This is the mode used most often. As can be seen, the setting of the two voltages will have a direct impact on the number of counts reported for a given sample. The determination of what these voltage settings should be must be done such that the optimum performance of the detector is obtained for those voltage regions. This is the purpose of a plateau. 2.03.26 State the method of performing a voltage plateau on counting systems at your site. DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material (Insert site-specific information here.) In conjunction with initial system setup and calibration by the vendor, two voltages plateaus are performed--alpha voltage and beta voltage. For P-10 gas the alpha plateau is started at about 400 volts and the beta plateau at about 900 volts. The plateaus are developed by plotting the gross counts accumulated for each radionuclide. Each time that a count is completed, the high voltage is incremented a specific amount, typically 25 to 50 volts, and another count is accumulated. This is repeated until the end of the range is reached, typically about 1800 volts. With the high voltage set at the starting point, few or no counts are observed because of insufficient ion production within the detector. As the voltage is increased, a greater number of pulses are produced with sufficient amplitude to exceed the discriminator threshold, and are then accumulated in the counter. There will be a high voltage setting where the increase in counts levels off (see Figure 8). This area is the detector plateau. Further increases in high voltage result in little change in the overall count rate. The plateau should remain flat for at least 200 volts using a Sr/Y-90 source, and this indicates the plateau length. Between 1750 and 1850 volts the count rate will start to increase dramatically. This is the avalanche region, and the high voltage should not be increased any further. E Statistics l off is called the rve and selecting a point 50 to 75 volts above the knee and ess than 2.5%. This ensures that minor changes in high voltage e sample count. Poor counting gas or separation of the methane very high slope of the plateau. Upon initial system setup and and sets the optimum operating voltages for the sys nerated each time the counting gas is changed. es used to minimize error and the fundamentals of binomial n of these fundamentals in a nu ualify the student to perform any tasks independently. TIONS 72% .7dpm D Counting Errors an ctor’s The region where the counts lev ating voltage is chosen by viewing the plateau c e knee and where the slope per 100 volts is in high voltage fects on t of the methane 10 can result in a em setup and calibration the vendor determine e sys Thereafter, plateaus should be g This lesson addressed the measu of binomial statistics, as well as the applicati nvironment. Completion of the unit does not dently. EXAMPLE PROBLEM SOL 4.2 0.2272 100 22 1441A 5.5 Instr of the plateau. The oper

chosen by viewing the plateau curve and selecting a point 50 to 75 volts above t where the slope per 100 volts is less than 2.5%. This ensures that minor change fects on the sample count. Poor counting gas or separatio 10 can result in a very high slope of the plateau. Upon initial sys calibration the vendor determines and sets the optimum operating voltages for t This lesson addressed the measures used to minimize error and the fundamental clear counting Completion of the unit does not qualify the student to perform any tasks indepe DO OE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and d Statistics Instru uctor’s Material The region where the counts leve el off is called the knee of the plateau. The oper ating voltage is chosen by viewing the plateau cu urve and selecting a point 50 to 75 volts above th he knee and where the slope per 100 volts is l less than 2.5%. This ensures that minor changes s in high voltage will have negligible effects on th he sample count. Poor counting gas or separationn of the methane and argon in P-10 can result in a very high slope of the plateau. Upon initial syst tem setup and calibration the vendor determiness and sets the optimum operating voltages for th he system. Thereafter, plateaus should be ge enerated each time the counting gas is changed. SUMMARY This lesson addressed the measurres used to minimize error and the fundamentals s of binomial statistics, as well as the applicatioon of these fundamentals in a nuclear counting e environment. Completion of the unit does not q qualify the student to perform any tasks indepen ndently. EXAMPLE PROBLEM SOLU UTIONS 2.03-1 200.0 σ 12.3 2.03-2 X 2 = 2858/200 = 14.29 9 2.03-3 2840 12500 0.2272 0.2272 100 22. E E = = × = .72% 2.03-4 4325 14416 0.3 A = = 6.7dpm 2.03-5 1 5.5 0.18 CF = = DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material 5 1750 0.2 2 50 σ = + 2.03-6 250 2σ = 1.26 = 1.96 25 10 2σ = 1.96(5) = 9.8 250 cpm = 1000 dpm 0.25 cld 9.8 cpm = 39 dpm 0.25 cld 2.03-7 3500 counts R S +B = = 1750 cpm 2minutes 3500 counts = 1750 −10 = 1740 cpm 10 counts 2minutes R B = = 0.2 cpm 50min utes = 29.6 R S = 1749.8 cpm TS = 2minutes 2σ 5 = 29.6 ×1.96 = 58 T B = 50 minutes Therefore, the net count rate should be reported as: 1740 +/- 58 cpm 2σ 2.03-8 562 + 62 2σ5 = 1.96 1 2σ5 = 1.96 624 R S = 562 − 62 = 500 cpm 2σ5 = 1.96(24.98) 2σ = 49 Therefore, the net sample count rate and associated error is: 500 ± 49cpm(2σ) III. SUMMARY This unit addressed the measures used to minimize error, fundamentals of binomial statistics and application of these fundamentals in a nuclear counting environment. http:1.96(24.98 DOE-HDBK-1122-2009 (Revised 2013) Module 2.03 Counting Errors and Statistics Instructor’s Material IV. EVALUATION Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% should be the minimum passing criteria for examinations. DOE-HDBK-1122-2008 Module 2.04 Dosimetry Instructor’s Guide 2.04-1 Course Title: Radiological Control Technician Module Title: Dosimetry Module Number: 2.04 Objectives: 2.04.01 Identify the DOE external exposure limits for general employees. 2.04.02 Identify the DOE limits established for the embryo/fetus of a declared pregnant female general employee.

→ 2.04.03 Identify the administrative exposure control guidelines at your site, including those for the: a. General Employee b. Member of the Public/Minor c. Incidents and emergencies d. Embryo/Fetus → 2.04.04 Identify the requirements for a female general employee who has notified her employer in writing that she is pregnant. 2.04.05 Determine the theory of operation of a thermoluminescent dosimeter (TLD). 2.04.06 Determine how a TLD reader measures the radiation dose from a TLD. 2.04.07 Identify the advantages and disadvantages of a TLD compared to a film badge. → 2.04.08 Identify the types of beta-gamma TLDs used at your site. → 2.04.09 Identify the types of neutron TLDs used at your site. → 2.04.10 Determine the requirements for use of TLDs used at your site. → 2.04.11 Determine the principle of operation, and the types used, for the personnel neutron dosimeters used at your site. → 2.04.12 Determine the principle of operation of self-reading dosimetry (SRD) used at your site. → 2.04.13 Determine the principle of operation, and guidelines for use, for the alarming dosimeters used at your site. → 2.04.14 List the types of bioassay monitoring methods at your site. 2.04.15 List different uses of area monitoring dosimeters. DOE-HDBK-1122-2008 Module 2.04 Dosimetry Instructor’s Guide 2.04-2 References: 1. "Basic Radiation Protection Technology"; Gollnick, Daniel; 5th ed.; Pacific Radiation Corporation; 2008. 2. ANL-88-26 (1988) "Operational Health Physics Training"; Moe, Harold; Argonne National Laboratory, Chicago. 3. "DOE Radiological Control Standard"; U.S. Department of Energy, 2008. 4. 10 CFR Part 835 (2007) "Occupational Radiation Protection". Instructional Aids: 1. Overheads 2. Overhead projector/screen 3. Chalkboard/whiteboard 4. Lessons learned DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-3 I. MODULE INTRODUCTION A. Self-Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation This lesson will introduce the types of instruments used to measure external and internal radiation to people. Dosimetry is the quantitative assessment of radiation received by the human body. There are several types of dosimeters in use worldwide. This material is valuable to all radiological control personnel since dosimeters are the only direct method to measure and document personnel radiation exposure and ensure regulatory compliance with applicable limits. C. Overview of Lesson 1. Dosimetry terms 2. DOE limits 3. Site administrative guidelines 4. TLDs 5. Site dosimetry 6. Bioassay assessment methods D. Introduce Objectives II. LESSON OUTLINE A. DOSIMETRY TERMS Understanding the terminology used in discussing dosimetry and exposure to ionizing radiation is essential for RCTs to do their job. 1. Absorbed Dose (D) O.H.: Objectives Majority from 835.2 Refer to the definitions provided in the Study Guide and review terms with class. DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-4 2. Equivalent Dose (HT) 3. Whole Body 4. Extremity 7. Committed Equivalent Dose (HT,50) 8. Radiation Weighting Factor (wR) 9. Committed Effective Dose (E50) 10. Total Effective Dose (TED) 11. Annual Limit on Intake (ALI) 12. Derived Air Concentration (DAC) 13. Bioassay 14. In Vivo 15. In Vitro 16. Background 17. Declared Pregnant Worker B. DOE LIMITS 1. Limits are the legal maximum values stated in 10 CFR 835.

To exceed these values is to violate the law. Programs must be in place to ensure that exposures to ionizing radiation are kept below these levels. To accomplish this Administrative Control Levels are selected well below the regulatory limits. These control levels are usually multi-tiered with increasing levels of authority required to approve higher Administrative Control Levels. 2. Annual dose limits are based on a calendar year (January 1st through December 31st). For assigning internal equivalent dose received from intakes (committed effective dose and committed equivalent dose), the total 50-year committed dose received is assigned to the time of the intake even though the actual dose is proportionally received over the 50-year period. 3. See Table 3 for dosimetric equivalencies for circumstances when an individual conducts multiple activities involving both activities under 10 CFR 835.1(b)(1) and excluded activities, e.g., activities involving NRC licensed activities. Explain that the terms were revised in the 2007 amendment to 10 CFR 835 Objective 2.04.01 See Table 2 See Table 3 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-5 a. General Employees 1) Whole body (internal + external) - 5 rems (0.05 sievert) 2) Lens of the eye - 15 rems (0.15 sievert) 3) Extremities - 50 rems (0.5 sievert) 4) Organ or tissue and skin - 50 rems (0.5 sievert) b. Minors/Public - 0.1 rem (0.001 sievert) c. Embryo/Fetus of Declared Pregnant Workers - 0.5 rems (0.005 sievert) per gestation period d. Emergency Exposures e. Planned Special Exposures C. SITE ADMINISTRATIVE GUIDELINES 1. Radiological Workers (Insert site specific information here) 2. Non-Radiation Worker (Insert site specific information here) 3. Exposure from Incidents or Emergencies (Insert site specific information here) 4. Embryo/fetus (Insert site specific information here) D. TYPES OF DOSIMETRY 1. As a result of irradiation, some solid substances undergo changes in some of their physical properties. 2. These changes amount to storage of the energy from the radiation. 3. Since the energy is stored, these materials can be used for dosimeters. The features that have been studied include: 10 CFR 835.202 10 CFR 835.207 & .208 10 CFR 835.206 Objective 2.04.02 DOE G 151.1-4, Chapter 7 10 CFR 835.204 Objective 2.04.03.a Objective 2.04.03.b Objective 2.04.03.c Objective 2.04.03.d DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-6 a. Optical density changes 1) Optical density changes involve a change in the color of some types of plastics and glass. 2) In glass, the dose range is 103 to 106 rads (10 to 104 gray). The range for plastics is 106 to 109 rads (104 to 107 gray). 3) An example, film badges, provides low range, 10 mR to 10 R, for personnel and high range, 1 R to 1,000 R for accident readings. b. Thermoluminescence 1) Thermoluminescence (TL) is the ability of some materials to convert the energy from radiation to a radiation of a different wavelength, normally in the visible light range. 2) There are two categories of thermoluminescence. a) Fluorescence - This is emission of light during or immediately after irradiation (within fractions of a second) of the phosphor. This is not a particularly useful reaction for TLD use. b) Phosphorescence - This is the emission of light after the irradiation period. The delay time can be from a few seconds to weeks or months. This is the principle of operation used for thermoluminescent dosimeters.

3) The property of thermoluminescence of some materials is the main method used for personnel dosimeters at DOE facilities and will be discussed in further detail. E. TLD OPERATION 1. TLD's use phosphorescence as their means of detection of radiation. 2. Electrons in some solids can exist in two energy states, called the valence band and the conduction band. The difference between the two bands is called the band gap. 3. Electrons in the conduction band or in the band gap have more energy than the valence band electrons. Example - TV or computer monitor screen Objective 2.04.05 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-7 4. Normally in a solid, no electrons exist in energy states contained in the band gap. This is a "forbidden region." 5. In some materials, or if impurities are added, defects in the material exist or are made that can trap electrons in the band gap and hold them there. These trapped electrons represent stored energy for the time that the electrons are held. This energy is given up if the electron returns to the valence band. 6. In most materials, this energy is given up as heat in the surrounding material, however, in some materials a portion of energy is emitted as light photons. This property is called luminescence. F. TLD Reader 1. Basic principle of operation a. Heating of the TL material causes the trapped electrons to return to the valence band. When this happens, energy is emitted in the form of visible light. b. The light output is detected and measured by a photomultiplier tube and a dose is then calculated. c. A typical basic TLD reader contains the following components: 1) Heater 2) Photomultiplier tube 3) Meter/recorder 2. Glow curve a. Obtained from heating process. b. The light output from TL material is not easily interpreted. Multiple peaks result. 1) As the material is heated, electrons trapped in "shallow" traps are released. This results in a peak as these traps are emptied. The light output drops off as these traps are depleted. See figure 1 - "Electron Entrapment" See figure 2 - "Thermoluminescence" Objective 2.04.06 See figure 3 - "TLD Reader" See figure 4 - "Glow curve" DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-8 2) As heating continues, the electrons in deeper traps are released. This results in additional peaks. Usually the highest peak is used for calculations. The area under the curve represents the radiation energy deposited. c. After the readout is complete, the TLD is annealed at a high temperature. This process essentially zeroes the TL material by releasing all trapped electrons. The TLD is then ready for reuse. G. ADVANTAGES AND DISADVANTAGES OF TLDs 1. Advantages (primarily as compared to film badges) a. Able to measure a greater range of doses. b. Doses may be easily obtained. c. They can be read on site instead of being sent away for developing. d. Quicker turnaround time for readout. e. Reusable. 2. Disadvantages a. Each dose cannot be read out more than once. b. The readout process effectively "zeroes" the TLD. H. SITE BETA/GAMMA TLDs (Insert site specific information here) I. SITE NEUTRON TLDs (Insert site specific information here) J. DOE EXTERNAL DOSIMETRY GENERAL PROVISIONS 1. Dosimetry shall be provided to and used by: a. General employee expected equivalent dose to the whole body > 0.1 rem (0.001 sieverts); or > 10% of limits for extremities, organs, and other tissues.

b. Declared pregnant worker expected to receive 0.05 rem (0.0005 sievert) or more during the gestation period. Objective 2.04.07 Objective 2.04.08 Objective 2.04.09 10 CFR 835 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-9 c. Minors likely to receive 50% of Occupational Dose Limits or more in a year. d. Public entering controlled areas likely to receive external equivalent dose to the whole body of 0.05 rem (0.0005 sievert) or more in one year. e. Individuals entering a high or very high radiation area. 2. Neutron dosimetry provided when applicable threshold is likely to exceeded due to neutron radiation. 3. Issued to individuals knowledgeable of proper use and worn only by assignee. 4. Issuance of dosimeters should be discouraged for individuals other than those where there is a likelihood of being occupationally exposed to levels above monitoring thresholds. 5. Dosimeters should be returned at required intervals. Individuals not returning dosimeters should be restricted. 6. Primary dosimeters should be worn on the chest area or between the waist and the neck. 7. Individuals should not be assigned multiple primary dosimeters during different periods of the dosimeter process year (exchange of primary dosimeter for multi-badging is acceptable); and avoid exposure of dosimeter to non- occupational sources. 8. When dosimeters are lost, damaged, or contaminated, the individual should place work in a safe condition, exit and notify the RCO. Reenter only after review and approval. K. SITE REQUIREMENTS FOR USE OF TLDs (Insert site specific information here) L. SITE PERSONNEL NEUTRON DOSIMETERS (Insert site specific information here) M. POCKET AND ELECTRONIC DOSIMETERS 1. Provide real time dose indication. 2. Shall be issued for entry into High or Very High Radiation Area. Objective 2.04.10 Objective 2.04.11 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-10 3. Should be issue when planned activity levels exceed 0.05 rem (0.0005 sievert) or 10% of control levels. 4. Should be issued when required by RWP. 5. Worn with primary dosimetry and located on chest area, on or between the waist and the neck. 6. Should be read periodically and should not exceed 75% of full scale. 7. Authorized work should cease when supplemental dosimeter indicates total dose or dose rate is > than expected. 8. When supplemental dosimeters differ by more than 50% from primary dosimeters and the primary result is >0.1 rem (0.001 sievert), an investigation should be initiated. N. SITE SELF-READING DOSIMETERS (Insert site specific information here) 1. Self Reading Pocket Dosimeters (SRPD) a. Direct reading ion chamber. b. Utilizes two electrodes: 1) Fiber electrometer (fixed and moveable components) 2) Metal frame c. As chamber is ionized the charge is decreased on the movable and fixed fiber. d. The movement of the fiber is proportional to the dose received. O. SITE ALARMING DOSIMETRY (Insert site specific information here) P. INTERNAL DOSIMETRY REQUIREMENTS Objective 2.04.12 See figure 5 - "SRPD" Note: SRPDs with steel walls are usually insensitive to beta and low energy gamma See figure 6 -"SRPD Reading" Objective 2.04.13 Re-enforce difference between "internal" and "external" dose DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-11 1. Internal dose evaluation programs shall be conducted for:

a. General employees - likely to receive 0.1 rem (0.001 sievert) or more committed effective dose. b. Declared pregnant workers - likely to receive an intake resulting in an equivalent dose of 10% of the limit (or 0.05 rem [0.0005 sievert]). c. Minors - likely to receive a committed effective dose in excess of 50% of limit (or 0.05 rem [0.0005 sievert]). d. Public - likely to receive a committed effective dose in excess of 50% of limit (or 0.05 rem [0.0005 sievert]). 2. Estimation shall be based on bioassay results rather than air concentration values unless air concentration values are more reliable or bioassay results are unavailable. 3. Follow-up bioassay monitoring is typically required when results indicate a committed effective dose of 0.1 rem (0.001 sievert) or more. 4. A bioassay program should be considered for personnel routinely exposed to surface or airborne contamination or to radionuclides readily absorbed through the skin. 5. Personnel are required to submit bioassay samples. 6. Personnel shall be notified of positive bioassay results. Q. BIOASSAY ASSESSMENT METHODS 1. General a. Today's technology has not produced a device that allows accurate determination of internal exposure following the entry of radioactive materials into the body. b. The method that is used to determine internal dose contributions relies on calculation of dose to affected portions of the body based on the quantities of radioactive materials in the body. Thus, the real problem becomes one of quantifying the amount of material present. c. Bioassay is the term that is used to describe the assessment of the quantity of radioactive material present in the body. There are currently two types of bioassay measurements employed in nuclear industries: 10 CFR 835.402 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-12 1) In vivo - analysis of living tissue. 2) In vitro - analysis of excreted samples. d. Bioassay programs are designed to fulfill two needs: 1) Evaluate effectiveness of contamination control practices. a) Routine bioassay programs utilize submission and analysis of samples from workers in facilities where the likelihood of intake exists. b) Primarily limited to urinalysis due to ease of sample collection. c) Also includes initial, routine, and termination whole body counts. 2) Evaluate potential consequences of accidental inhalation or ingestion of large quantities of radioactive materials. a) Can involve all types of bioassay measurements with collection and analysis of nasal, urine, and fecal samples. b) Whole body counts provide immediate indications for given radionuclides if individual(s) involved are free of external contamination. 2. In vivo measurements a. The amount of materials is estimated by counting radiation emitted by radioactive materials in the body. b. Only good for radioactive materials which emit gamma radiation of sufficient abundance and energy to be detected and statistically measured. c. With use of expensive, sophisticated spectroscopy, most contributors (radionuclides present) can be identified. d. Site In vivo methods (Insert site specific information here) e. Advantages Objective 2.04.14 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-13 1) No sample required. 2) Results obtained quickly. 3) Some equipment design allows field use. 4) Time and manpower requirements minimized. f. Disadvantages

1) Limited to detection and measurement of gamma emitters. 2) Individual must be free of external contamination. 3) Long count times for identification. 4) Effects of background. 5) Complex calibration procedure and calibration equipment. 6) Expense. 7) Quantification error due to differences in tissue structure from one person to another as compared to calibration phantom. 3. In Vitro Measurements a. The amount of material present in the body is estimated using the amount of materials present in excretions or secretions from the body. b. Samples include urine, feces, blood, sputum, saliva, hair and nasal discharges. c. Calculation requires knowledge of and use of metabolic models which allow use of activity in samples to be related to activity present in the body. d. Resulting dose calculations to quantify committed and effective doses are estimates. 1) This is due partly to use of default values for measurements that cannot be readily made such as mass of particular organs, volumes of particular fluids, etc., in lieu of actual values for individual involved. Remember that reference man is an average. DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-14 2) Another contributing factor is different metabolism from one individual to another. e. Types of analysis 1) Urinalysis - indicates intake of primarily soluble material. 2) Fecal analysis - primarily indicates intake of insoluble material. Provides relatively rapid indication. 3) Sputum - may contain insoluble material initially deposited in the lung and later eliminated by ciliary action. 4) Saliva - may be use to estimate uptake of tritium oxide. 5) Nasal discharge - indication of the deposition of the coarsest inhaled particles in the nose. f. Site in vitro methods (Insert site specific information here) g. Advantages of in vitro measurements 1) Can be used for estimation of neutron doses using activation product concentration in hair and blood (32P and 24Na). 2) Can be used to quantify presence of materials which decay by alpha and beta emission to allow detection and measurement with external detector systems. h. Disadvantages 1) Requires sample submission and analysis. 2) Time and manpower requirements. 3. Bioassay Scheduling Program a. Contamination found at a given site will depend on the materials that are used and produced at the site. Thus, the materials that internal dosimetrists are primarily concerned with will change from one site to another as well. Objective 2.04.14 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-15 b. Baseline/Routine/Exit Evaluations (Insert site specific information here) c. Special Evaluations (Insert site specific information here) d. Investigation Levels (Insert site specific information here) e. Medical Uses (Insert site specific information here) R. AREA MONITORING DOSIMETERS 1. Area monitoring dosimeters are often used to record and document radiation levels in routinely occupied areas adjacent to areas where radiation or radiological operations exist. Note: This type of monitoring does not apply when the radiation hazard of concern arises from low-energy beta sources (e.g., 14C, 3H). 2. Establishment and maintenance of a comprehensive area monitoring program can demonstrate that doses outside Radiological Buffer Areas are negligible, and help to minimize the number of areas requiring the issuance/use of personnel dosimeters.

Minimizing the number of personnel dosimeters issued saves in the costs of operating the dosimetry program and reduces costs associated with maintaining personnel with enhanced training and qualifications. 3. Area monitoring dosimeters are also used to help characterize workplace conditions to verify the effectiveness of physical design features, engineering controls, and administrative controls. In addition, area monitoring dosimeter results can be used to support dosimetry investigations where personnel express concerns about their work environments and exposure to ionizing radiation. 4. Finally, area (and equipment) monitoring dosimeters are useful for the determination of dose rates and/or integrated doses for: Objective 2.04.15 DOE-HDBK-1122-2009 Module 2.04 Dosimetry Instructor’s Guide 2.04-16 a. equipment and/or areas with suspected high dose rates; b. devices emitting pulsed radiation not accurately measured with portable survey instruments; c. highly collimated beams of radiation; and d. radiological incidents. III. SUMMARY A. Review major topics 1. Dosimetry terms 2. DOE limits 3. Site administrative guidelines 4. TLDs 5. Site dosimetry 6. Bioassay assessment methods B. Review learning objectives IV. EVALUATION Evaluation shall consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% shall be the minimum passing criteria for examinations. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-1 Course Title: Radiological Control Technician Module Title: Contamination Control Module Number: 2.05 Objectives: 2.05.01 Define the terms "removable and fixed surface contamination," state the difference between them and list common methods used to measure each. 2.05.02 State the components of a radiological monitoring program for contamination control and common methods used to accomplish them. 2.05.03 State the basic goal of a contamination control program and list actions that contribute to its success. 2.05.04 State the basic principles of contamination control and list examples of implementation methods. 2.05.05 List and describe the possible engineering control methods used for contamination control. 2.05.06 State the purpose of using protective clothing in contamination areas. 2.05.07 List the basic factors which determine protective clothing requirements for personnel protection. References: 1. "DOE Radiological Control Standard"; U.S. Department of Energy, 2008. 2. "The Health Physics and Radiological Health Handbook," Shleien; 1992. 3. 10 CFR Part 835 (2007) "Occupational Radiation Protection". Instructional Aids: 1. Overheads 2. Overhead projector/screen 3. Chalkboard/whiteboard 4. Lessons learned DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-2 I. MODULE INTRODUCTION A. Self-Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation Contamination control is probably one of the most difficult and challenging tasks the Radiological Control Technician will encounter. C. Overview of Lesson 1. Types of Contamination 2. Assessing Contamination Hazards 3. Basic Goal of Contamination Control 4. Contamination Control Measures 5. Basis for Establishing Protective Clothing Requirements D. Introduce Objectives II. MODULE OUTLINE A. TYPES OF CONTAMINATION

Contamination is simply defined as radioactive material in an unwanted location, e.g., personnel work areas, etc. Two types are possible: 1. Fixed Contamination - Radioactive surface contamination that is not easily transferred to other personnel or equipment through normal contact. 2. Removable Contamination - Radioactive surface contamination that is easily transferred to other personnel or equipment through normal contact. O.H.: Objectives Objective 2.05.01 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-3 3. Removable contamination is measured by a transfer test using a suitable sampling material. Common materials used for the monitoring are the standard paper disk smear or cloth smear. The standard technique involves wiping approximately 100 cm2 of the surface of interest using moderate pressure. A common sampling practice used to ensure a 100 cm2 sample is to wipe a 16 square inch "S" shape on the surface (i.e., four inches by four inches). Qualitative, large area wipe surveys may be taken using other materials, such as Masslin cloth or Kimwipe, to indicate the presence of removable contamination. These are commonly used when exact levels of contamination are not required. 4. Fixed contamination is measured by use of a direct survey technique. This technique, commonly referred to as "frisking," indicates the total contamination on a surface apparent to the detector from both fixed and removable. To evaluate the fixed component the removable level must be subtracted from the total, when non-removable levels are to be recorded. Appendix D to 10 CFR 835 lists contamination levels in units of dpm/100 cm2. Typical evaluation of fixed contamination monitoring includes adjusting the portable instrument count rate (counts per minute) to account for the area of the monitoring instrument (probe area) and the instrument efficiency to obtain units of dpm/100 cm2. Footnote 4 to Appendix D states that when “removable contamination on objects of surface area less than 100 cm2 is determined, the activity per unit area shall be based on the actual area and the entire surface shall be wiped”. For example, for an object with a total surface area of 50 cm2, the entire object would be wiped and the count result would be divided by the counting efficiency and multiplied by an area adjustment factor of two (100 cm2/50 cm2) to get a result in units of dpm/100 cm2. A similar approach may be used for fixed contamination monitoring of objects with surface area less than 100 cm2. However, care must be taken in monitoring very small objects and the sensitivity of the monitoring protocol should be evaluated. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-4 B. ASSESSING CONTAMINATION HAZARDS In order to acquire the radiological information necessary for contamination control, the presence of contamination must be identified. In order to achieve this, a radiological monitoring program must be applied. The components are: • Constant monitoring • Area and equipment surveys • External personnel surveys • Personnel internal monitoring and bioassay 1. Constant monitoring - There are various types of constant monitoring instruments installed throughout facilities to warn personnel of radiation and contamination hazards. Identify the types of instrumentation used in the constant monitoring. a. Some instruments are permanently installed, and some

instruments are portable to allow movement from place to place as deemed appropriate. b. Continuous air monitor (CAM) - These instruments sample the air in specific locations continuously for radioactive contamination. Other methods of continuously monitoring for airborne contamination are also used. Objective 2.05.02 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-5 1) Filter monitors draw air through a moving particulate filter, which is then monitored by a detector system. 2) Direct monitors pull air flow through an internal detector to directly identify radioactive materials present. 3) CAMs can give both a visual and audible alarm to warn personnel of the presence of airborne contamination. c. Process monitoring systems - These systems monitor certain operations in various facilities to alert operators of abnormal conditions which might lead to the release of excessive amounts of radioactivity to the facility or environment. 2. Area and equipment surveys - Surveys are conducted routinely throughout facilities to locate sources of radiation and contamination. Pre-job surveys are performed to evaluate hazards and determine work limitations and physical safeguards within locations identified. a. Direct instrument surveys 1) Various types of portable survey instrumentation are used to measure the presence of radioactive contamination on a floor or surface. 2) This is the only method available to detect "fixed" surface contamination. b. Smear surveys 1) A disk smear is wiped over an area of 100 square centimeters and counted with proper instrumentation to determine the activity of the nuclides present in units of dpm/100 cm2. a) Disk smears are small so they are usually used in an area of suspected contamination. b) Experience will dictate to the surveyor where contamination is most likely to occur and hence those areas that should be surveyed with disk smears. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-6 2) Many routine contamination surveys are taken with a chemically treated cloth called a masslinn. a) Cloth is lightly pushed over a specified area and scanned with an appropriate detector to detect the presence of contamination. b) If contamination is detected, a more thorough disk smear survey should be performed. c) Large area wipes are used only as an indication of removable surface contamination. d) Disk smears are required if contamination levels are to be quantified. 3. External Personnel Surveys - Personnel surveys are either performed by the individual (self-monitoring) using hand- held or automated instruments or by a RCT. Monitoring by a RCT is usually conducted whenever contamination of the body or clothing is suspected, or as required by exit monitoring when self-monitoring is not allowed. The following describes the general types of hand-held or automated instruments that are commercially available. a. Personnel monitors - Sensitive hand held detectors used by personnel to identify contamination on themselves whenever contamination is suspected. 1) Portable Geiger-Mueller (GM) or scintillation detectors that are installed at strategic locations throughout the facilities. 2) These monitors are used whenever exiting contaminated areas or RBAs. b. PCMs (Personnel Contamination Monitors) provide personnel with an external whole body monitoring system. 1) PCMs are typically located at the RBA exits in

facilities with a high occupancy factor. 2) Contamination detectors within the monitors are capable of performing a survey of the whole body in a period of a few seconds, dependent upon background radiation levels and the personnel contamination limit of concern. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-7 3) These systems provide a more reliable method of locating personnel contamination over hand-held instruments. c. Portal monitors - Portal monitors are "door frame" type devices which provide a final monitoring point to ensure contamination is not spread outside the facility to other facilities or the general public. Personnel are required to use (pause and walk through) this type of monitoring system prior to exiting specified areas. d. Personnel surveys - These are performed by RCTs whenever contamination of clothing or the body is suspected, or as required when friskers or automated instruments are not available. 1) The whole body should be surveyed with special attention given to areas which are more likely to become contaminated. 2) A minimum survey of the hands, arms, and front portions of the body must be performed upon completion of work or prior to leaving the area for glovebox, laboratory fume hood, sample station, or localized benchtop operations. 3) Contamination of the feet (shoes) would indicate removable surface contamination on the floor just traversed. 4) The nose and mouth should be surveyed upon discovery of facial contamination or if airborne contamination was detected in the work area to determine if bioassay sampling is required. 5) The nose can be swabbed with Q-tips and the swab counted in a smear counter. 6) Contamination of the nose or mouth may indicate airborne contamination. 7) All open wounds must be monitored since contaminants can be readily absorbed into the body. 8) Upon detecting personnel contamination, follow-up area and/or equipment surveys may be necessary to determine the source of contamination and the extent the contamination has spread, if any. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-8 4. Personnel internal monitoring - A routine program of internal contamination monitoring is conducted as a final check on contamination control procedures. Typical programs consist of external whole/partial body counting and/or urinalysis. a. In-vivo bioassay (whole/partial body counting) - Individual is placed inside an array of very sensitive detectors to measure the activity and energies of gamma ray emissions from inside the body. Information can be used to determine the amount and identify the type of nuclides present. b. In- vitro bioassays - Performed by collection of urine or feces samples from an individual to determine type and activity of the nuclides present in bodily waste. 1) Information is used to approximate the amount of nuclides present in the body by their calculated rate of elimination. 2) Can be used to assess the presence of non-gamma emitting nuclides. C. BASIC GOAL OF CONTAMINATION CONTROL Once the presence of radioactive material has been located, the basic goal underlying any effective contamination control program is to minimize contaminated areas and maintain contamination levels as low as reasonably achievable. 1. If the presence of removable contamination is discovered, decontamination is a valuable means of control. a. In some situations, this is not always possible.

1) Economical conditions: Cost of time and labor to decontaminate a location out- weighs the hazards of the contamination present. 2) Radiological conditions: Radiation dose rates or other radiological conditions present hazards which far exceed the benefits of decontamination. 3) Operating conditions: Some areas, e.g., hot cells, will be contaminated due to normal operations. b. Other means of control, such as engineering controls, administrative procedures, or personnel protective equipment, must be initiated when decontamination is not possible. Objective 2.05.03 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-9 2. "Good Housekeeping" is a prime factor in an effective contamination control program. It involves the interactions of all groups within the facility. Each individual must be dedicated to keeping "his house clean" to control the spread of contamination. Every possible effort should be made in all operations to confine the spread of radioactive materials to the smallest possible area. 3. A sound preventive maintenance program can prevent many radioactive material releases. 4. All material taken into or out of contaminated areas should be controlled. 5. Regardless of the precautions taken, radioactive materials will occasionally escape and contaminate an area. 6. Radiological Control Technicians should always be alert for potential violations to the basic principle of contamination control. a. Use of improper contamination control methods b. Bad work practices c. Basic rule or procedure violations d. Radioactive material releases or liquid spills 7. Radiological Control Technicians should always ensure that the proper procedures to avoid the spread of contamination are followed or implemented. D. CONTAMINATION CONTROL MEASURES Controlling the spread of contamination is probably the most difficult and challenging task the Radiological Control Technician will encounter. The basic principles of contamination control are: • Access/Administrative Controls • Engineering Controls • Personnel Protective Measures • Decontamination • Preventive Methods 1. Access/Administrative Control Objective 2.05.04 Objective 2.05.05 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-10 Once the location of contamination has been identified and quantified and radiological areas have been established, we must adequately control access to these areas. Boundaries of radiological areas must be clearly marked. This is accomplished by using radiological postings and tags identifying entrances into these areas to restrict access. Two basic access control points are used in contamination control. a. The primary access control point in a facility is the entry and exit portal between the clean area and the radiologically controlled area or RBA. The success of a control program is based on controlling the movement of personnel and equipment between these areas to prevent release of contamination to a clean location. b. Secondary access control points (perhaps the most important) are set up within the RBAs to control access between surface contamination areas and non- contaminated areas. Yellow and magenta rope, tape, chain, or similar barriers are used to identify boundaries. Step-off-pads provide a recognizable demarcation to personnel between the contaminated area and the RBA. 1) Special requirements will always be established for

entry and exit through these access control points. 2) When radiological conditions are severe, the access control point will be continuously manned by Radiological Control Technician. 3) Proper procedures must be established and observed for crossing the SOP to prevent spread of contamination out of the area. 4) All tools and/or equipment used in contaminated areas which are unmonitored shall be placed in plastic bags or securely wrapped in plastic before being removed from the area. 5) All personnel and materials exiting the area shall be monitored to ensure they are free of contamination. 2. Engineering Controls - There are several specific methods of engineering control which can be utilized. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-11 a. Ventilation - The design of permanent or temporary ventilation systems needs to be such that air flow is from clean areas to RBAs, to areas of moderate contamination, to areas of high contamination, and finally to a exhaust system capable of removing any contamination from the air. Slight negative pressure is typically maintained in buildings/rooms where potential contamination exists. b. Containment - On jobs with very high contamination potential, a plastic tent, (greenhouse or hut) can be built around the work area to confine all contamination to as small an area as possible. 1) A portable ventilation exhaust system (such as HEPAs) may be used to control air flow in the containment hut and remove airborne contamination. 2) Where possible, small containment devices, such as glove boxes, glove bags, or hoods can be used to contain the contamination depending on the nature and location of the work being performed. 3) Contaminated tools or equipment are placed in plastic bags, or securely wrapped in plastic, before being moved outside a contaminated area. 4) When possible, wrapping tools or equipment prior to entry can help control contamination during use inside the contaminated area. c. Design and Control - Design of facilities should be such that efficiency of maintenance, operations, and decontamination is maximized. 1) Components should be selected that minimizes the buildup of radioactivity. 2) Support facilities should be included that provide for the donning and doffing of protective clothing and for personnel monitoring. 3) Personnel traffic should be routed away from contaminated areas. 3. Personnel Protective Measures - If engineering methods are not adequate, then personnel protective measures, such as protective clothing and respiratory equipment, will be used. Objective 2.05.06 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-12 a. The purpose of protective clothing is to keep contamination off the skin and clothing of the workers. 1) Protective clothing allows personnel to work inside a contaminated area with removable contamination and to exit the area without spreading contamination to uncontrolled areas. 2) Use of protective clothing alone will not guarantee complete elimination of personnel contamination and is not a substitute for implementing proper controls, but if used properly, protective clothing will afford a high degree of protection. 3) All personnel entering contaminated areas with removable contamination will be required to wear certain items of protective clothing. 4) Types of clothing required will vary depending upon

the contamination levels and the nature of the work to be performed. b. Some type of respiratory protective equipment will be required for work in areas where very high contamination levels exist or airborne contamination is present. 3. Decontamination - Line management is responsible for ensuring prompt decontamination, where practical, of facilities, tools, equipment, and material so that contamination can be minimized in the workplace. Reasonable efforts should be directed toward the decontamination and unconditional release of these items rather than their disposal as radioactive waste. 4. Preventive Methods - The following are practical methods used for the prevention/control of contamination. a. Identify and repair leaks before they become a serious problem. b. Establish adequate work controls before starting jobs. c. While conducting pre-job briefs, discuss measures that will help reduce or prevent contamination spread. d. Change out gloves or protective gear as necessary to prevent cross-contamination of equipment. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-13 e. Pre-stage areas to prevent contamination spread from work activities. f. Cover piping/equipment below a work area to prevent dripping contamination onto less contaminated areas. g. Cover/tape tools or equipment used during the job to minimize decontamination after the job. h. Follow good work practices such as good housekeeping and cleaning up after jobs. i. Confine the spread of radioactive material releases by a sound preventive maintenance program. j. Control and minimize all material taken into or out of contaminated areas. E. BASIS FOR ESTABLISHING PROTECTIVE CLOTHING REQUIREMENTS 1. The basic factors that determine the type and extent of protective clothing required are: a. type and form of contamination b. levels of contamination c. type of work being performed d. potential for increased levels of contamination e. the area of the body at risk f. competing hazards, i.e., asbestos, heat stress, etc. 2. Once the types of protection needed are established, the most efficient protective clothing must be selected from the different articles of protective clothing available for use. a. Whole body protection 1) Laboratory coat a) Provides protection from low levels of contamination. b) Only applicable when the potential for body contact with contaminated surfaces is very low. Objective 2.05.07 DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-14 c) Lab Coats are generally worn for hands-off tours and inspections in areas with removable contamination at levels 1 to 10 times the values in Table 2-2 of the Radiological Control Standard. d) Lab coats may also be worn during benchtop, laboratory fume hood, sample station, and glovebox operations. 2) Coveralls a) Provides protection from low to moderate levels of DRY contamination. b) Protection is low when body contact with contaminated surfaces is prolonged (since contamination can be ground into the cloth). c) Protection is low when the surface is wet. d) Degree of protection can be increased by use of more than one pair at a time to protect the body. e) Not effective against radionuclides with high permeation properties (gases, tritium, etc.). 3) Plastic coveralls a) Provides protection from high levels of dry contamination. b) Provides protection from wet forms of contamination.

c) Provides limited protection from tritium and other highly permeating radionuclides being transported through the coveralls to the skin surface. 4) Disposable coveralls a) Used for work involving mixed hazards, i.e., asbestos, PCBs, etc., where reuse is not desirable. b) Types of suits are tyvek, gortex, etc. which provide moderate protection from radioactive contamination. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-15 c) Disposable coveralls can be easily torn. b. Hand protection 1) Surgical gloves a) Minimal requirement b) Normally used in only light contamination work areas c) High degree of dexterity d) Fairly easily torn or punctured 2) Rubber gloves a) Lightweight b) Provides good gripping surface c) Normally used in moderate to heavy contamination locations d) Greater puncture, abrasion and solvent resistance, but afford a lower degree of dexterity than surgical gloves. 3) Neoprene gloves a) Synthetic rubber gloves mounted to various containment devices to allow access by the wearer into the device. b) Used to provide protection for the wearer when working inside a containment device in which highly contaminated materials are present. c) Usually of arm length attached to dry boxes, glove boxes and bags, or other cabinets. d) Provides a gas tight seal to the structure. e) Gloves are normally taped to the sleeve of the lab coat, coveralls, plastic suit, etc. and are tabbed to permit easy removal. 4) Cotton glove liners DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-16 May be worn inside standard gloves for comfort, but should not be worn alone or considered as a layer of protection. 5) Leather or canvas work gloves Should be worn in lieu of or in addition to standard gloves for work activities requiring additional strength or abrasion resistance. c. Foot protection 1) Booties: Used to protect lower leg area below coveralls from contamination. Different constructions used: a) Plastic b) Cloth (sometimes called cloth shoe covers) 2) Shoe covers: Worn over booties to provide a second layer of protection and provide traction to wearer. Normally are constructed of plastic or rubber. 3. Respiratory protection a. Full-face masks: Used to filter particulate radionuclides and/or radioactive Iodine from the breathing air of the wearer when the surrounding atmosphere is not immediately dangerous to the life and health of the wearer. b. Supplied air systems: Used to prevent inhalation of particulate and gaseous radionuclides by the wearer in a non-life threatening atmosphere. c. Self-contained breathing apparatus (SCBA): Used to provide a portable source of breathing air to the user when entering an atmosphere which may be immediately dangerous to life and health. d. Medical approval, training, and fit testing are required prior to respiratory protection use. 1) Systems should be in place to verify these criteria in the field. 2) The wearer should be clean shaven in the area of fit. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-17 3.) The wearer should perform fit checks of their respirators to ensure a proper seal. 4. Facility Protective Clothing Requirements (Insert facility specific material here) III. SUMMARY A. Review major topics 1. Types of Contamination 2. Assessing Contamination Hazards 3. Basic Goal of Contamination Control

4. Contamination Control Measures 5. Basis for Establishing Protective Clothing Requirements B. Review learning objectives IV. EVALUATION Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% should be the minimum passing criteria for examinations. DOE-HDBK-1122-2009 Module 2.05 Contamination Control Instructor’s Guide 2.05-18 This page intentionally left blank. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-1 Course Title: Radiological Control Technician Module Title: Air Sampling Program/Methods Module Number: 2.06 Objectives: 2.06.01 State the primary objectives of an air monitoring program. 2.06.02 Describe the three physical states of airborne radioactive contaminants. 2.06.03 List and describe the primary considerations to ensure a representative air sample is obtained. 2.06.04 Define the term "isokinetic sampling" as associated with airborne radioactivity sampling. 2.06.05 Identify the six general methods for obtaining samples or measurements of airborne radioactivity concentrations and describe the principle of operation for each method. a. Filtration b. Volumetric c. Impaction/impingement d. Adsorption e. Condensation/dehumidification f. In-line/flow-through detection 2.06.06 Describe the general considerations for selection of an air monitoring method. 2.06.07 State the purpose of the five primary types of airborne radioactivity samplers/monitors: a. Personal air samplers (breathing zone) b. High volume/flow rate air samplers c. Low volume/flow rate air samplers d. Portable continuous air monitors e. Installed continuous air monitoring systems 2.06.08 List the factors that affect the accuracy of airborne radioactivity measurements and describe how these factors affect sample accuracy. → 2.06.09 Describe the site air monitoring program that includes monitoring frequencies, calculational methods, applicable derived air concentration limits, and methods for determining radon interference. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-2 References: 1. "Introduction to Health Physics"; Cember, Herman; 4nd ed.; McGraw-Hill Medical; 2008. 2. "Basic Radiation Protection Technology"; Gollnick, Daniel; 5th ed.; Pacific Radiation Corporation; 2008. 3. Moe Harold, Operational Health Physics Training, ANL- 88-26, Department of Energy, Argonne National Laboratory, Chicago, 1988. 4. "Air Monitoring", Chapter 10 of Implementation Guide for Use with 10 CFR 835, "Occupational Radiation Protection". Instructional Aids: 1. Overheads 2. Overhead projector/screen 3. Chalkboard/whiteboard 4. Lessons learned DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-3 I. MODULE INTRODUCTION A. Self-Introduction 1. Name 2. Phone number 3. Background 4. Emergency procedure review B. Motivation Before the proper internal exposure control methods can be determined for personnel, an estimate of the airborne radioactivity concentration must be obtained. Additionally, airborne radioactivity measurements are necessary to ensure that the control measures assigned are effective and continue to be effective. C. Overview of Lesson 1. Purpose and objectives of airborne radioactivity sampling 2. The nature of airborne radioactivity 3. Representative air samples 4. Basic sampling methods

5. Selection of the air sampling method 6. Primary types of air samplers 7. Basic air sample calculations D. Introduce Objectives II. MODULE OUTLINE A. PURPOSE AND OBJECTIVES OF AIRBORNE RADIOACTIVITY SAMPLING 1. Airborne radioactive contaminants are of concern to the radiological control organization due to the biological effects of the ionizing radiation emitted by those contaminants. O.H.: Objectives DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-4 2. Inhalation of radioactive airborne particles is one of the most important routes of entry of radionuclides into the human body. 3. This represents a relatively complicated process that depends on particle size distribution of the airborne particles, their dynamical behavior in air, and the physical and chemical properties of the particles after deposition in the respiratory tract. 4. Air monitoring is performed to identify and monitor airborne radioactive material in order to control the intake of airborne radioactive material by workers. 5. Regulations govern the allowable or limiting doses to an individual. a. The total effective dose of an individual is determined by combining the external and internal effective dose values. b. Typically, airborne radioactivity levels are maintained well below allowable levels to keep the internal dose contribution to the total effective dose small. c. Confirmation that airborne radioactivity levels are maintained low is accomplished by the airborne radioactivity sampling program. d. It is important to note that the individual equivalent dose from internal sources is not normally determined from air sampling analysis data, unless other information, such as bioassay data, is unavailable, inadequate, or internal dose estimates based on representative air concentration values are demonstrated to be as or more accurate. 6. It is necessary to be aware that the air monitoring program is only one element of a comprehensive radiation protection program. a. Individuals involved with the air monitoring program should interact with personnel working in other elements of the radiation protection program, particularly with individuals involved in contamination control and internal dosimetry. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-5 7. The primary objectives of an air monitoring program are: a. To measure the concentration of the radioactive contaminant(s) in the air by collection and analysis b. To identify the type and physical characteristics of the radioactive contaminant to help evaluate the hazard potential to the worker c. To evaluate the performance of airborne radioactivity control measures d. To assess air concentration data in order to determine if bioassay sampling should be initiated to verify whether an exposure has occurred, and if so, to determine the magnitude of the exposure. 8. Additionally, the air monitoring program must demonstrate that airborne radioactivity released to the general environment is maintained as low as reasonably achievable and below the allowable limits established by regulatory agencies. 9. The primary goal of the air monitoring program is to determine if the level of protection provided to the worker is sufficient to minimize the internal equivalent dose. a. Allowable concentration values, such as DACs, are used as an index of the degree of control needed and achieved.

b. Documented measurements of the airborne radioactivity concentrations are required to demonstrate that satisfactory control is achieved and maintained. 10. Air sampling is required when an individual is likely to receive an exposure of 40 or more DAC-hours in a year. Other situations requiring sampling are: a. to establish the need for posting of airborne radioactivity areas and to determine the need for respiratory protection for workers. b. to assess unknown hazards during maintenance on systems contaminated with radioactive material or when there is a loss of process controls. Objective 2.06.01 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-6 c. to assist in determining the type and frequency of bioassay measurements needed for a worker. d. to provide an estimate of worker exposures for situations where bioassay measurements may not be available or their validity is questionable. e. to develop baseline airborne radioactivity levels and verify containment integrity as necessary during startup of a new facility or new operation within an existing facility. f. where respiratory protection devices for protection against airborne radionuclides have been used. g. real-time monitoring is needed as necessary to detect and provide warning of increases in airborne radioactivity levels that warrant immediate actions to terminate the inhalation of airborne radioactive material. B. THE NATURE OF AIRBORNE RADIOACTIVITY 1. Airborne radioactive contaminants are generally divided into three categories, based on the physical state of the contaminant. a. Particulates b. Gases c. Vapors 2. Particulate contaminates are solid and liquid particles, ranging upward from molecular sizes (approximately 10-3 um), suspended in the air. a. Solids may be subdivided into fumes, dusts, and smokes, which are distinguished mainly by their mode of generation. b. Liquids are subdivided into mists and fogs, depending on the dispersion of the liquid particulates. c. The term "aerosols" is used to collectively refer to relatively stable suspensions of either solid or liquid particles in a gaseous medium. Objective 2.06.02 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-7 d. Generally, particulates are more readily retained in the lungs than are gases, but retention of particulates is highly dependent on particle size and solubility in the lung. e. While this suggests that particulate airborne contaminant sampling should measure particle size, this is not practically accomplished on a routine basis. f. Certain sampling instruments utilize the characteristics of particle size to separate larger particles from smaller particles (e.g., impactors.) g. This is an important factor in that the size range of particles retained in the respiratory tract is generally 1- 10 um. h. The retention of inhaled radioactive particles after deposition in the pulmonary region of the lung is strongly influenced by the dissolution characteristics of the particles. 1) Dissolution in the lungs allows clearance into the blood and the rest of the systemic circulation. 2) For this reason, the various chemical forms of radioactive particles are classified with respect to their potential solubility in the lungs. 3) These are Type S for the very insoluble particle

that takes years to clear from the lungs; Type M for the somewhat more soluble particles that take weeks to dissolve and clear into the systemic circulation; and Type F for the relatively soluble particles that dissolve in a matter of days in the lung. 3. Gases are substances that, under normal conditions of temperature and pressure, exist in the gaseous phase. a. The retention of the gases in the body from poor inhalation is so radioactive gases are usually treated as an external source of exposure. b. Radioactive gases typically found are the fission product gases, such as xenon and krypton, and naturally occurring radon. c. While the gases contribute primarily to external exposure, the particulate daughters to which they decay can contribute to internal exposure. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-8 4. Vapors are considered the gaseous phase of a substance that is normally a solid or liquid under normal conditions of temperature and pressure. a. Airborne vapor sampling is most commonly done for radioiodine and tritium. b. The contaminant may be dispersed in vapor form at abnormal conditions of temperature and pressure. c. However, as the temperature and pressure conditions return to "normal," the contaminant will return to its normal solid or liquid form, or become a particulate. d. Sampling methods for vapors should isolate or measure the contaminant regardless of whether the vapor or particulate form is present. C. REPRESENTATIVE AIR SAMPLES 1. To ensure that the sample is representative of the actual conditions. a. The airborne radioactivity concentration entering the sample line must be representative of the airborne radioactivity concentration in the air near the sampling device. b. The airborne radioactivity concentration entering the sampling inlet must be representative of the airborne radioactivity concentration at the point of concern, or the air that is breathed, i.e., breathing zone. 2. When obtaining an air sample, care must be taken to ensure that the sample obtained is representative of the air around the sampling device. a. This is particularly important for sample lines that directly sample an air flow, such as a stack or duct monitor. b. Air flow into sampling lines needs to be balanced with respect to the flow of air around the probe or sample inlet. c. If there is not a relative balance between these velocities, particles may be thrown in or out of a sampling probe rather than being sampled in a representative fashion. Objectives 2.06.03 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-9 d. To ensure the sample is representative, the flow rate in the sample line or inlet must be the same as the flow rate in the system, such as the duct or stack. 1) When the sample line velocity is equal to the system velocity at the sample point, it is called isokinetic sampling e. If the velocities are not the same, or isokinetic, then discrimination can occur for smaller or larger particles. This occurs because the inertia of the more massive particles prevents them from following an airstream that makes an abrupt directional change. 1) If the velocity of the sample airstream is > the velocity of the system airstream, then the larger particles can not make the abrupt change and are discriminated against in the sample, i.e., the smaller particles are collected more efficiently.

2) If the velocity of the sample airstream is < the velocity of the system airstream, then the small particles do make the abrupt change and are discriminated against in the sample, i.e., the larger particles are collected more efficiently. f. To minimize particle losses, sampling lines should be as short (less than six feet preferred) and straight as possible to avoid sample deposition along the walls of the tube. When possible, sample lines should be vertical instead of horizontal to prevent gravimetric settling of large particles. g. The sampling line should have no more than one bend and be made of conducting material. 3. There are other factors to consider for maximizing the efficiency of airborne radioactivity detection. a. Self-absorption losses, e.g., dust loading, should be minimized. This is especially critical for alpha detection. b. Air in-leakage between the sample intake and the sample collection medium should be eliminated to the greatest degree possible by instrument design. Objective 2.06.04 See Fig. 1 - "Isokinetic Sampling" DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-10 c. The system and mechanisms within the instrument for sample collection should be designed and constructed to minimize deterioration and to facilitate decontamination. This is more critical in areas with corrosive atmospheres. 4. When obtaining an air sample, care must be taken to ensure that the sample obtained is representative of the air at the point of interest (the breathing zone). a. Depending on the source of the airborne contaminant, the concentrations within a work area can vary over several orders of magnitude. b. The sample taken should be representative of the air entering the nose and mouth of the individual workers since the data obtained may be used to estimate potential worker intakes. c. The best method to ensure a representative breathing zone sample is to sample the air at the individual's nose and mouth. d. This sampling method may not always be practical and general work area sampling may be the alternative. e. Care must be exercised in the selection of the number and placement of the general area air samplers to ensure that the sample is as representative as possible. D. BASIC SAMPLING METHODS 1. Basically, three types of samples are collected: a. A volumetric sample in which part of the atmosphere is isolated in a suitable container, providing the original concentration of the contaminant at a particular place and time. b. An integrated sample which concentrates the contaminant on some collecting medium, providing an average concentration over the collection time. (Sometimes called a "grab" sample if collected in a short period of time.) c. A continuous sample where the sample air flow is directed past or through a detection device providing a measurement of the activity per unit volume of air. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-11 2. Breathing zone air monitoring should be performed continuously in areas where workers are likely to exceed 40 DAC-hr exposure in a year. Breathing zone air monitoring is used to identify possible worker internal exposure and the need for follow-up bioassay measurements. 3. Source-specific air sampling is performed near an actual, or likely, release point in a work area.

This is typically used to verify containment integrity, documenting airborne radioactivity levels, and providing guidance on personnel protective measures (e.g., determining when respiratory protection is required). 4. Grab air sampling is used for temporary or nonroutine (e.g., emergency response) situations and as a backup for other types of air sampling in the event of equipment failure. a. Portable air sampling equipment is typically used for operations requiring a grab sample. b. Sample flow rates may vary depending upon the specific application, but should always allow collection of a sample volume adequate to ensure the minimum detectable activity of the sampling and counting system is no greater than 2% of an ALI. 5. There are six general methods for obtaining samples or measurements of airborne radioactivity concentrations. a. Filtration b. Volumetric c. Impaction/impingement d. Adsorption e. Condensation/dehumidification f. In-line/flow-through detection 6. Filter samplers employ filtration of the air as the method of concentrating the airborne radioactive particulate (aerosol) contaminants. Objective 2.06.05 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-12 a. Filtration is the most common sampling method employed for particulates because it is relatively simple and efficient, but is ineffective as a sampling method for gases and vapors. b. The filter sampling technique employs an air mover, such as a vacuum pump, to draw air through the removable filter medium at a known flow rate for a known length of time. 1) If the flow rate and sample time are known, the total volume collected can be calculated. 2) After analysis of the filter medium to determine the amount of radioactive material collected on the filter at the time of the sample, the airborne concentration can also be calculated. c. The filtration medium selected for a sample depends on several factors: the collection efficiency required, the flow resistance of the medium, and the mechanical strength of the filter, pore size, the area of the filter, the background radioactive material of the filter, cost, self- absorption within the filter, and chemical solubility. d. A wide choice of filters is available. The most common types are: 1) Cellulose-asbestos filters 2) Glass fiber filters 3) Membrane filters Membrane filters are manufactured with various pore sizes and can be dissolved in organic solvents and analyzed in a counter, e.g., a liquid scintillation counter. 7. Volumetric samplers employ a sample container into which the sample is drawn, by some method, and isolated for analysis. a. Several methods are employed to draw the sample into the container. 1) The container may be evacuated by a vacuum pump and isolated away from the sample location. The container is opened at the sample location to draw the air into the container. The sample is sealed in the container and removed for analysis. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-13 2) An air mover, such as a vacuum pump, may be employed at the sample location to draw a representative atmospheric sample into the container. 3) The container could be filled with water, isolated and taken to the sample location. The water is poured out of the container, drawing the air sample into the container as the water pours out. b. This method can be employed for particulates, gases,

and vapors. 8. Impingers or impactors concentrate particulate contaminants on a prepared surface by abruptly changing the direction of the sample air flow at some point in the sampler. a. Particles are collected on a selected surface as the airstream is sharply deflected. Due to their inertia, the particles are unable to follow abrupt changes in airstream direction. b. The surface on which the particles are collected must be able to trap the particles and retain them after impaction. Several methods are commonly used to trap the particles, such as: 1) Coating the collection surface with a thin layer of grease or adhesive. 2) Immersing the collection surface in a fluid, such as water or alcohol, which is then analyzed after the sample is collected. c. Impingers and impactors may utilize several stages or impingement distances to discriminate for or against different particle sizes. d. Impactors are frequently used to isolate particles larger than the undesired smaller particles, such as transuranics over radon daughters, or radon daughters over fission products. 9. Adsorber sampling devices concentrate the contaminants by causing them to adhere to the surface of the adsorption medium. a. Adsorption is the adhesion of a substance to the surface of another substance through bonding. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-14 b. The adsorption medium is granulated or porous to increase the surface area available for trapping of the contaminant. c. The technique employs an air mover to draw and collect the sample through the adsorption media. d. Adsorbers, such as activated charcoal, silica gel, and silver zeolite, are commonly used to collect organic vapors and non-reactive gases and vapors. 1) Activated charcoal is used primarily for radioiodine sampling, but does trap noble gases, such as xenon, krypton and argon. 2) Silica gel is primarily used for tritium oxide vapor sampling. 3) Silver zeolite is used for radioiodine sampling when trapped noble gases would interfere with the radioiodine analysis. e. Particulates would be "filtered" by the absorption media and must be filtered out before the adsorption process to prevent interference during the analysis of the media. 10. Condensation or dehumidifier sampling devices employ a "cold trap" to condense water vapors in the sampled atmosphere and provide a liquid sample for further analysis. a. Some means, such as liquid nitrogen or a refrigeration unit is utilized to cool the condensation surface and cause condensation of the water vapor as it passes over the cold surface. b. The collected water is frequently analyzed using a liquid scintillation counter. c. Calculations must include the relative humidity and temperature of the air at the time the sample is taken to determine the concentration of water vapor per unit volume of air. d. This technique is normally only applied for sampling tritium oxide vapor (HTO or T2O). 11. In-line or flow-through samplers employ an air mover to direct the sample air flow through or past the detection device. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-15 a. This method is employed for radionuclides which are difficult to collect or detect by other means. b. Because the air flow passes directly outside the detector or actually through the inside of the detector, the air must be filtered for particulates or vapors that could accumulate on or in the detector.

c. In-line detectors are used to measure gaseous activity after filtration and adsorption have been accomplished. d. Flow-through detectors are employed for radionuclides, such as tritium, which emit low-energy radiation, that could not otherwise pass through the detector window. 12. The various sampling methods may be combined into one sampler or monitor. a. Some samplers employ the filtration method for particulates, the adsorption method for vapors and the volumetric grab-sample method for gases (in that order). Some advantages of combining these methods are: 1) One vacuum pump supplies the air flow for all the samples. 2) All the samples are drawn at the same time to minimize the amount of time spent by the technician drawing samples. b. In addition, some monitors have detectors installed to monitor each sample and provide an immediate readout as well as other capabilities, such as alarms, data records, process controls, and trending. E. SELECTION OF THE AIR SAMPLING METHOD 1. It is critical that the proper air sampling method and equipment be selected because: a. The data obtained must be meaningful and accurate to adequately assign radiological control measures. b. Improper selection and use may incorrectly indicate a safe environment where an airborne radiological hazard exists or leads to unneeded postings where no hazard exists. 2. The general considerations for the selection of an air sampling method include several factors. Objective 2.06.06 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-16 a. The environmental conditions in the area where the sample is to be obtained. 1) Humid conditions may preclude the use of some methods, such as paper filtration devices or charcoal canisters, because water vapor loading of the medium will change the collection efficiency and flow rate. 2) High temperature environments may cause some samplers to overheat if run for long periods of time. 3) Explosive gases may be present which could present an explosion hazard for samplers with electric motors not designed for such environments. 4) Dusty areas could cause excessive sample loading which will reduce sampler flow rates and potentially overheat the sampler. 5) Corrosive environments may lead to the deterioration of the sampling device. b. The physical characteristics of the area in which the sample is to be obtained. 1) An electrical outlet may not be available or close, and a battery powered sampler would be better suited. 2) Close spaces or passages may preclude the use of movable CAMs or heavy samplers. c. The energy and type of radiation of the radionuclide being monitored. This will dictate the type of CAM or analysis equipment required to determine the airborne radioactivity concentration. d. The expected concentration level. This will determine the length of sample time and type of sampler required. 1) Low-level concentrations will require larger volumes to reduce statistical errors and meet minimum sensitivity levels of the analysis equipment. 2) Large volume samples obtained over a long time period are best obtained by samplers designed to run for long periods. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-17 3) If immediate readout of information is needed, then collection and analysis are done at the same time. 4) If not, then samples may be taken and removed to a central analysis location.

e. The physical state of the airborne contaminant. Dependent upon whether the contaminant is either gas, vapor or aerosol, will dictate the type of sampler and sample medium that is required. f. The type of survey required. Specific methods, such as breathing zone samples, routine general area samples, general work area samples, general trending over time, etc., also determines the type of equipment that is selected. g. Procedural requirements. This may dictate a particular type of sample method and/or sample medium for a given application. 1) Check the appropriate procedures prior to sampler selection. 2) Ask supervision and experienced technicians for their input. F. PRIMARY TYPES OF AIR SAMPLERS 1. The five primary types of airborne radioactivity samplers/monitors are: a. Personal air samplers (breathing zone) b. High volume/flow rate air samplers c. Low volume flow rate air samplers d. Portable continuous air monitors (CAMs) e. Installed continuous air monitoring systems 2. Personal air samplers (PAS) provide an estimate of the airborne radioactivity concentration in the air the worker is breathing during the sampling period. a. The PAS may also be used to determine if the protection factor for respiratory equipment is exceeded, to compare with other workplace air samples, and to verify the effectiveness of engineered and administrative controls. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-18 b. Personal air samplers are small portable battery- powered devices which sample the air in the breathing zone of the worker's environment, making allowances to eliminate interferences the sampler's themselves may have on a worker's activities. Some characteristics are: 1) The device contains a small battery-powered pump that is calibrated to a flow rate approximately 1/10 (2 liters per minute) the breathing rate of a worker performing light activity. 2) The sampling line terminates in a filter cassette which contains the filtration medium for the radioactive particulate contaminants. 3) The sample filter cassette is attached close to the nose and mouth of the individual. 3. Portable high volume/flow rate samplers provide an estimate of the airborne radioactivity concentration at a particular location in a short period of time. a. Portable high flow rate samplers are used to collect airborne aerosols on a filter paper (filtration) or on a greased planchet (impaction). b. Portable high flow rate samplers can also be used to collect radioiodine samples using activated charcoal cartridges (adsorption) as long as the maximum flow rate of the cartridge is not exceeded or a correction factor is used. c. These samplers do not have installed detectors and the sample must be removed from the sampler and analyzed on separate analysis equipment. d. The high volume/flow rate samplers may be used to: 1) Provide a routine "slice of time" estimate of the general area airborne radioactivity 2) Verify boundaries of areas posted for airborne radioactivity 3) Or monitor the airborne radioactivity related to a specific work activity. e. High volume samplers typically use flow rates of at least 10 cubic feet per minute (cfm). See Fig. 2 - "High Volume Sampler" DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-19 1) Although these samplers are noisy and not intended for continuous duty, the shorter sample times allow for greater sensitivity.

4. Low volume/flow rate samplers provide an estimate of airborne radioactivity concentrations averaged over a longer period of time at a particular location. a. Portable low volume/flow rate samplers are used to collect samples for aerosols on filter paper (filtration) and radioiodine on an adsorption medium, such as an activated charcoal cartridge. b. Low volume/flow rate samplers may be used to provide average airborne radioactivity estimates over a period of time for: 1) Commonly traversed areas that normally have a low probability of airborne radioactivity problems 2) Areas not commonly traversed with a higher probability of airborne radioactivity problems 3) Backup samples in areas where airborne radioactivity problems are discovered by other means 4) Work maintenance activities normally characterized by low airborne radioactivity concentrations. c. Low volume samplers generally have flow rates set at approximately 20 lpm, the breathing rate of a worker performing light activity. 1) Although these samplers must run longer for reasonable sensitivity, they are generally quiet and can be used for continuous duty. 5. Portable CAMs provide an estimate of airborne radioactivity concentrations averaged over time at a particular location, and provide immediate readout and alarm capabilities for preset concentrations. a. These air monitors are portable low flow rate (~20 lpm) sampling systems, containing the necessary sampling devices and built-in detection systems to monitor the activity on the filters, cartridges, planchettes and/or chambers in the system. See Fig. 3 - "Low Volume Sampler" DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-20 b. The system may provide a visual readout device for each type of sample medium, a recording system for data, and computer functions such as data trending, preset audible and visual alarms/warning levels and alerts for system malfunctions. c. Typical CAMs provide information on alpha and/or beta/gamma particulates (filtration), radioiodine activity (adsorption) and noble gas activity (volumetric chamber or in-line detector). d. Portable CAMs can be utilized as: 1) Low volume general area samplers 2) Monitors with alarm capabilities for areas where airborne radioactivity conditions may quickly degrade 3) Trending devices in selected areas 4) Devices to locate system leaks, if used with the appropriate length hose or tubing. 6. Installed CAMs provide an estimate of airborne radioactivity concentrations averaged over time at a fixed, designated location, and provide immediate local and remote readout and alarm capabilities for preset concentrations. a. These air monitors are fixed low flow rate sampling systems, and contain the necessary sampling devices and built-in detection systems to monitor the activity of selected areas or airstreams. b. The system may provide a local and remote visual readout device, a recording system for data, and computer functions such as data trending, preset audible and visual alarms/warning levels and alerts for system malfunctions. c. Installed CAM applications include: 1) Fixed installations capable of sampling several locations through valved sample lines. 2) Stack monitors 3) Duct monitors DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-21 7. Factors affecting the accuracy of airborne radioactivity measurements include:

a. Sample is not representative of the atmosphere being sampled b. Sample is not representative of the air being breathed by the worker c. Incorrect or improperly installed sampling media for the selected sampler, causing leak or improper flow rates d. Malfunctioning, miss-operated, or miscalibrated sampling device, causing errors in flow rate measurements e. Accuracy and operation of the timing device, causing errors in the time value f. Accuracy and operation of the flow rate measuring device, causing errors in the flow rate value g. Mishandling of the sample media causing cross- contamination or removal of sample material h. Changes in the collection efficiency of the medium due to sample loading, humidity and other factors i. Improper use or selection of analysis equipment j. Inherent errors in the counting process due to sample geometry, self-absorption, resolving time, backscatter and statistical variations k. Mathematical errors during calculations due to rounding of numbers and simple mistakes l. Incorrect marking of samples and inaccurate recording of data 8. It is important that the personnel performing the sample collection and analysis minimize the magnitude of these errors to ensure that accurate and reliable data is obtained for the assignment of internal exposure control methods. Objective 2.06.08 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-22 G. BASIC AIR SAMPLE CALCULATIONS 1. Once the air sample is collected and analyzed, calculations must be performed to determine the amount of activity per unit volume. 2. The specific calculations for particular sampling methods are not covered in this lesson; however, some basics are necessary for each calculation. 3. The analysis of the sample provides the activity of the sample at the time of the sample analysis. a. This value may be corrected for decay for the time period between when the sample was taken to when it was analyzed. 1) This is especially true for short-lived radionuclides. 2) This correction may not be necessary for very long- lived radionuclides. b. The volume of the sample must be determined from the sample data recorded, such as flow rates at the beginning and end of the sample, and sample time period. c. The basic calculation listed below would also include the conversions necessary for the desired units such as dpm/liter to µCi/cc. d. The calculation would also include correction factors, as necessary, for: 1) Interference of other radionuclides, such as radon and thoron daughters 2) Collection efficiency 3) Counter efficiency 4) Self-absorption by the sample media 5) Counter background. 6) Temperature and pressure as applied to flow rate 4. Many errors are inherent or induced in the sampling analysis process and affect the accuracy of the resulting data. DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-23 5. The operator of the sampling and analysis equipment must be aware of these points of error to ensure the resulting data is as accurate as possible. (Insert site specific material here) III. SUMMARY A. Review major points 1. Purpose and objectives of airborne radioactivity sampling 2. The nature of airborne radioactivity 3. Representative air samples 4. Basic sampling methods 5. Selection of the air sampling method 6. Primary types of air samplers 7. Basic air sample calculations B. Review learning objectives IV. EVALUATION Evaluation should consist of a written examination comprised of multiple choice, fill-in the blank, matching and/or short answer questions. 80% should be the minimum passing criteria for examinations. Objective 2.06.09 DOE-HDBK-1122-2009 Module 2.06 Air Sampling Program/Methods Instructor’s Guide 2.06-24 This page intentionally left blank. DOE-HDBK-1122-2009 Module 2.07 Respiratory Protection Instructor’s Guide 2.07-1 Course Title: Radiological Control Technician Module Title: Respiratory Protection Module Number: 2.07 Objectives: 2.07.01 Explain the purpose of respiratory protection standards and regulations. 2.07.02