Module 7: Perform Monitoring Activities Using Scintillation Detectors
RPT 113Instructional Resources
Module 7: Perform Monitoring Activities Using Scintillation Detectors
Table of Contents:
Resources Key......
Module Readings and Homework......
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler”.....
Transfer Scenario “Determine Gross Gamma Counts of Environmental Samples”....
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas Monitor”
Transfer Scenario “Monitor Personnel for Contamination”......
Module Assessment Items
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler”.....
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas Monitor”
Suggested Labs......
ACAD References......
Resources Key
This refers to: / This reference:ACAD / National Academy for Nuclear Training, Uniform Curriculum Guide for Nuclear Power Plant Technician, Maintenance, and Nonlicensed Operations Personnel Associate Degree Programs, ACAD 08-006.
DOE-SG / Office of Environmental, Safety and Health: Radiological Control Technician Training Site Academic Training Study Guide Phase I, Project Number TRNG-0003
Available at: File is located under the Docs/General Curriculum/DOE materials folder.
G. / Gollnick, D. (2006). Basic Radiation Protection Technology, 5th Ed. Pacific Radiation Corporation, Altadena, CA.
Spectrum / Spectrum Spectroscopy Techniques Lab Manual (Instructors and Student Versions)
Supl. Lab / Supplemental Lab Manual (instructors and Student Versions)
Module Readings and Homework
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler”
Core Concept: NaI Scintillation DetectorHomework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 271-279
DOE SG 1.13-23 through 1.13-27 / N/A / G., Chap. 7, # 21, 25
DOE SG 1.13.09
Core Concept: Detector Efficiency
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 243-244, 277-278
DOE SG 2.03-18 though 2.03-20 / DOE SG 2.03.13 / DOE SG 2.03.12
Core Concept: Portable air monitors (low volume samplers)
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 10, 416-425
DOE SG 2.18-2 though 2.18-6 / N/A / DOE SG 2.18.01 through 2.18.04
Core Concept: Calculation of air concentrations
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
DOE SG 2.06-19 / N/A / N/A
Transfer Scenario “Determine Gross Gamma Counts of Environmental Samples”
Refer to readings and homework for primary scenario above.
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas Monitor”
Core Concept: Gas effluent monitoring/ Stack gas monitorsHomework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 10, 420-425
DOE SG 2.06-5 through 2.06-7 / N/A / N/A
Core Concept: Beta scintillations detectors
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
N/A / N/A / N/A
Core Concept: Alpha scintillations detectors
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 12, 500-501 / N/A / N/A
Transfer Scenario “Monitor Personnel for Contamination”
Refer to readings and homework for primary scenario above.
Module Assessment Items
Note: If instructors wish to increase the difficulty of any item,then we suggest you use it as the basis for an in-class discussion, and / or require students to write an explanation for why a particular choice is correct.
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler”
You are a Radiation Protection Technician for a hospital that utilizes radiopharmaceuticals for therapeutic treatment. Although you do not administer the radioisotopes, you are responsible for much of their storage, handling, and disposal as well as the disposition of contaminated waste generated in the facility. Much of the dry contaminated waste is compacted into 55-gallon metal drums for decay and disposal. In the areas where the isotopes and waste are packaged, the potential for airborne contamination exists. Because of the installed ventilation system with charcoal and HEPA filters, airborne radioactivity concentrations in work areas are consistently below 0.05 Derived Air Concentrations (DACs). One of your duties is to obtain air samples in the work areas and analyze them for specific isotopes to ensure airborne radioactivity levels are ALARA.
1. (Inference) You have taken an air sample in the work area and obtained the filter paper and charcoal cartridge containing the airborne radioactivity. You have used a NaI scintillation detector system and MCA to analyze both the filter and the charcoal cartridge. Twenty-minute counts were taken for each. The resulting gross activity of the filter is 0.05 μCi and the resulting gross activity of the charcoal cartridge is 0.025 μCi. Which of the following statements is correct concerning the particulate and iodine concentrations?
A.) The iodine concentration is twice the particulate concentration.
B.) The particulate concentration is 0.075 μCi
C.) The particulate concentration is twice the iodine concentration (Correct)
D.) The iodine concentration is 0.075 μCi.
2. (Prediction) Scintillation detectors utilize various types of scintillation material. How would the intrinsic efficiency of the detector change, for high energy photons, as the scintillation material density is decreased?
A.) The intrinsic efficiency of the detector would increase.
B.) The intrinsic efficiency of the detector would decrease. (Correct)
C.) The intrinsic efficiency of the detector would not change.
D.) The intrinsic efficiency for low energy photons is zero.
3. (Explanation) Which explanation best describes how iodine isotopes are typically collected for spectroscopic analysis?
A.) A volume of air including the iodine isotopes is sealed in a container and then analyzed.
B.) A volume of air is drawn through a filter to capture the iodine isotopes and then analyzed.
C.) The iodine isotopes are collected by impingement in a porous material and then the material is analyzed.
D.) The iodine isotopes are chemically bonded to a material and then the material is analyzed. (Correct)
4. (Explanation) Which explanation best describes how a scintillation detector differentiates between different isotopes?
A.) The light output of the photomultiplier tube is a function of the incident photon energy. The output signal of the crystal is a function of the light input, and therefore is proportional to the energy of the incident radiation.
B.) The light output of the crystal is a function of the incident photon energy. The output signal of the photomultiplier tube is a function of the light input, and therefore is proportional to the energy of the incident radiation. (Correct)
C.) The electron output of the crystal is a function of the incident photon energy. The output signal of the photomultiplier tube is a function of the electron input, and therefore is proportional to the energy of the incident radiation.
D.) The light output of the photocathode is a function of the incident photon energy. The output signal of the photomultiplier tube is a function of the light input, and therefore is proportional to the energy of the incident radiation.
5. (Prediction) You have started a low-volume air sampler operating in a work area to collect an air sample for gross airborne activity. You set the flow rate of the sampler at 20 liters per minute (lpm) and plan to operate the sampler for approximately 24 hours. During the sample collection time, welding was performed in the area which produced some smoke. How will an increase in airborne particulate, due to the welding smoke, likely change the sample volume and why?
A.) Increases the volume because welding smoke is lighter than air
B.) Decreases the volume because welding smoke clogs the sample filter (Correct)
C.) Does not change the volume because the sampler has a fixed flow rate
D.) Does not change the volume because the sampler has positive displacement flow
6. (Explanation) Which explanation best describes how a scintillation detector works?
A.) Incident radiation enters the photomultiplier tube where it is converted into electrons. The electrons enter the crystal where they are multiplied into a large pulse. The circuitry measures the electron pulse.
B.) Incident radiation enters the crystal where it is converted into electrons. The electrons enter the photomultiplier tube where they are converted into light. The circuitry measures the light.
C.) Incident radiation enters the crystal where it is converted into light. The light enters the photomultiplier tube where is is multiplied into a large pulse. The circuitry measures the light pulse.
D.) Incident radiation enters the crystal where it is converted into light. The light enters the photomultiplier tube where it is converted into electrons and multiplied into a large pulse. The circuitry measures the electron pulse. (Correct)
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas Monitor”
You have just started your evening shift as a Radiation Protection Technician at the Springfield University Research Reactor (SURR). The SURR is operated to support neutron activation research. Your major task this evening is to collect the weekly airborne effluent particulate, iodine, and noble gas samples for analysis. SURR utilizes a Canberra PING monitor to continuously monitor airborne effluents.
1. (Explanation) Which of the following explains why the effluent air passes through the three monitors (Iodine, Gaseous, Particulate) of a PING in a certain order?
A.) The noble gas analysis is last to allow the Iodines to decay and have minimal effect on the gas analysis.
B.) The particulate analysis is last so it allows the previous Iodine analysis to include particulates
C.) The noble gas analysis is last so the resulting air does not include particulates and Iodines. (Correct)
D.) The Iodine analysis is last so the resulting air does not include particulates and noble gases
2. (Explanation) Which of the following best explains how a scintillation detector measures incident radiation?
A.) The electrons produced in the photocathode are multiplied and measured and are proportional to the intensity of the incident radiation. (Correct)
B.) The light produced in the scintillation crystal is multiplied with a photomultiplier tube and measured and is proportional to the intensity of the incident radiation.
C.) The ionizations produced in the scintillation crystal produce a small current which is measured and is proportional to the intensity of the incident radiation.
D.) The light produced in the photocathode is multiplied with dynodes and measured and is proportional to the intensity of the incident radiation.
3. (Prediction) Which of the following would likely result from careless handling of the particulate filter removed from the PING?
A.) A higher calculated amount of iodine effluent
B.) A lower calculated amount of gaseous effluent
C.) A higher calculated amount of gaseous effluent
D.) A lower calculated amount of particulate effluent (Correct)
4. (Inference) Why does a scintillation detector not operate within one of the three operating regions (Ionization, Proportional, G.M.) of the gas amplification curve?
A.) It utilizes a vacuum for detection
B.) It operates at a higher voltage
C.) It operates at a lower voltage
D.) It utilizes a solid detector (Correct)
5. (Inference) A scintillation detector differentiates between alpha and beta radiation by what method?
A.) A removable beta shield
B.) Alpha radiation produces larger signals (Correct)
C.) Beta radiation produces larger signals
D.) A removable alpha shield
Suggested Labs
No Labs
ACAD References
ACAD1.1.8 Radiation Protection and Detection
- Explain the principles and operation of radiation detection and monitors including the following
3.2.2 Radiation Detection and Measurement Principals
- Explain the function of a scintillation (micro-r meters, liquid scintillation counters, zinc-sulfide alpha counters and probes), fission chamber and semiconductors (high-purity germanium, electronic dosimeters)
3.2.3 Radiological Survey and Analysis Instruments
- Identify the instruments available for performing contamination surveys such as the following
–Plastic scintillation detectors
- Explain the operating characteristics and basic electrical circuitry of counting and spectroscopy equipment (such as proportional counters, liquid scintillation detectors, high-purity germanium, zinc sulfide detectors)
- Identify factors that affect the statistical accuracy of radioactivity measurements, including count rate, background, count time, equipment efficiency, sample volume and sample geometry. Explain how the statistical accuracy of measurements can be improved
- Define the lower limit of detection (LLD)
- Perform LLD and minimum count rate calculations for various radioactivity measurements
- Explain the operating characteristics and use of the following radiological survey and analysis instruments:
–Alpha survey instrument *
- Explain the principles of operation of process radiation monitoring systems
- Explain the operating characteristics and use of monitoring devices including the following monitors:
–Noble gas air
–Particulate air
3.2.4 Sample Collection Equipment
- Operate the following air sampling equipment and describe when each is used:
–Low volume samplers
3.3.12 Radiological Incident Evaluation and Control
- Describe how to estimate beta and gamma dose rates from the following:
*ACAD is also referenced in other courses of the curriculum
Module Perform Monitoring Activities Using Scintillation Detectors
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