Perform Monitoring
Activities Using Scintillation
Detectors
ACADs (08-006) Covered
Keywords
Description
Supporting Material
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RPT 113
Instructional Resources
Module Perform Monitoring Activities Using Scintillation Detectors
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
Page 1
RPT 113
Instructional Resources
Module 7: Perform Monitoring Activities Using
Scintillation Detectors
Table of Contents:
Resources Key .................................................................................................................... 3
Module Readings and Homework ...................................................................................... 3
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler” ......... 3
Transfer Scenario “Determine Gross Gamma Counts of Environmental Samples”....... 4
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas
Monitor”.......................................................................................................................... 4
Transfer Scenario “Monitor Personnel for Contamination” ........................................... 4
Module Assessment Items .................................................................................................. 5
Primary Scenario “Monitor for Air Contamination Using Portable Air Sampler” ......... 5
Primary Scenario “Monitor for Iodine particulates and Nobel Gases Using Stack Gas
Monitor”.......................................................................................................................... 6
Suggested Labs ................................................................................................................... 7
ACAD References .............................................................................................................. 8
RPT 113 Instructor’s Guide
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
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RPT 113
Instructional Resources
Resources Key
This refers This reference:
to:
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
G.
Spectrum
Supl. Lab
Available at: http://nsedu.rnet.missouri.edu/docshare/. File is located
under the Docs/General Curriculum/DOE materials folder.
Gollnick, D. (2006). Basic Radiation Protection Technology, 5th Ed.
Pacific Radiation Corporation, Altadena, CA.
Spectrum Spectroscopy Techniques Lab Manual (Instructors and
Student Versions)
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 Detector
Readings
G., Chap. 7, 271-279
DOE SG 1.13-23 through 1.13-27
Core Concept: Detector Efficiency
Readings
G., Chap. 7, 243-244, 277-278
Homework (end of chapter)
Calculation Items
Non-calculation Items
N/A
G., Chap. 7, # 21, 25
DOE SG 1.13.09
Homework (end of chapter)
Calculation Items
Non-calculation Items
DOE SG 2.03.13
DOE SG 2.03.12
DOE SG 2.03-18 though 2.03-20
Core Concept: Portable air monitors (low volume samplers)
Homework (end of chapter)
Readings
Calculation Items
Non-calculation Items
G., Chap. 10, 416-425
N/A
DOE SG 2.18.01 through
2.18.04
DOE SG 2.18-2 though 2.18-6
Module Perform Monitoring Activities Using Scintillation Detectors
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
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RPT 113
Core Concept: Calculation of air concentrations
Homework (end of chapter)
Readings
Calculation Items
DOE SG 2.06-19
N/A
Instructional Resources
Non-calculation Items
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 monitors
Homework (end of chapter)
Readings
Calculation Items
Non-calculation Items
G., Chap. 10, 420-425
N/A
N/A
DOE SG 2.06-5 through 2.06-7
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.
RPT 113 Instructor’s Guide
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
Page 4
RPT 113
Instructional Resources
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)
Module Perform Monitoring Activities Using Scintillation Detectors
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
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RPT 113
Instructional Resources
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.
RPT 113 Instructor’s Guide
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
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RPT 113
Instructional Resources
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
Module Perform Monitoring Activities Using Scintillation Detectors
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
Page 7
RPT 113
Instructional Resources
ACAD References
ACAD
1.1.8 RADIATION PROTECTION AND DETECTION
 Explain the principles and operation of radiation detection and monitors
including the following
– Scintillation detectors
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
– Alpha scintillation detectors
– 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:
– Gross gamma counter
– 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:
– Iodine air
– Noble gas air
– Particulate air
3.2.4 SAMPLE COLLECTION EQUIPMENT
 Operate the following air sampling equipment and describe when each
is used:
– High volume samplers
RPT 113 Instructor’s Guide
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
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RPT 113
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– Low volume samplers
3.3.12 RADIOLOGICAL INCIDENT EVALUATION AND CONTROL
 Describe how to estimate beta and gamma dose rates from the
following:
– Airborne radioactivity (particulate, iodines, noble gases and tritium)
*ACAD is also referenced in other courses of the curriculum
Module Perform Monitoring Activities Using Scintillation Detectors
The Curators of the University of Missouri
Copyright © 2008-2009
A Product of DOL Grant # HG-15355-06-60
Page 9