RPT 113 Instructional Resources
Module 8: Perform Analysis of Water Samples Using Liquid Scintillation Counters (LSC)
Table of Contents:
Resources Key 2
Module Readings and Homework 2
Primary Scenario “Monitor for Beta Contamination in Waste Tank Water Samples” 2
Transfer Scenario “Monitor for Tritium Levels in Environmental Water Samples” 2
Module Assessment Items 3
Primary Scenario “Monitor for Beta Contamination in Waste Tank Water Samples” 3
Suggested Labs 4
ACAD References 5
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: http://nsedu.rnet.missouri.edu/docshare/. 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 Beta Contamination in Waste Tank Water Samples”
Core Concept: Liquid Scintillation Counters (LSC)Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 7, 267-271
DOE SG 1.13-27 to 1.13-28
DOE SG 2.19-8
DOE SG 2.19-12 to 2.19-13 / N/A / G., Chap.7, # 18, 19
Core Concept: Beta spectroscopy
Homework (end of chapter)
Readings / Calculation Items / Non-calculation Items
G., Chap. 2, 40
G., Chap. 7, 270-1
DOE SG 1.13-21 to 1.13-22 / N/A / DOE SG 1.13-08 (substitute LSC for proportional counters in the question)
Transfer Scenario “Monitor for Tritium Levels in Environmental Water Samples”
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 Beta Contamination in Waste Tank Water Samples”
You are a Radiation Protection Technician for a commercial research reactor facility that produces radiopharmaceuticals and provides neutron activation of materials for research. Waste water from the various systems at the facility is routinely discharged into the local sewer system. As required by federal law there are limits for radioisotopes discharged into sewer systems, so your facility routinely samples the waste water before any discharges are made. One of your job tasks is to sample and analyze the waste water for radioisotopes prior to discharge. You use a Liquid Scintillation Counter (LSC) to analyze for beta-emitting isotopes and a High Purity Germanium (HPGe) detector to analyze for gamma-emitting isotopes. You are familiar with the operation of the LSC and the HPGe detector and have performed this analysis many times by following a carefully written procedure. The procedure ensures the analyses are performed correctly and the same way each time. You are now performing the analysis of beta-emitters, using the LSC.
1. (Inference) As you perform the analysis of beta-emitters using the LSC, you notice that one of the sample vials has a scratch on its side. How would the scratch likely affect the sample results and why?
A.) It would cause the resultant count to be in error because it would affect the light transmittance of the vial and consequently the detected counts. (Correct)
B.) It would not cause the resultant count to be in error because LSCs typically utilize coincidence counting to rule out all inconsistencies in the process.
C.) It would cause the resultant count to be in error because it would adversly affect the accuracy of the count from both scintillation detectors.
D.) It would not cause the resultant count to be in error because the vial condition has no adverse effects on the counts.
2. (Prediction) How would the LSC counting result be affected by a radioactively contaminated scintillation cocktail?
A.) Counts would be lower than actual
B.) Counts would be higher than actual. (Correct)
C.) There would be no change in the counts.
D.) It would depend on the type of cocktail used.
3. (Explanation) Which explanation best describes why a LSC is the best type of detector for low energy beta radiation?
A.) Its electronic discriminator can discriminate as low as 0.5 MeV.
B.) Its detector geometry of 2π has a geometric efficiency near 100%.
C.) Its liquid scintillator has an intrinsic efficiency near 100%. (Correct)
D.) Its aluminum detector window has an areal density of only 7 mg/cm2.
4. (Explanation) Which explanation best describes how a LSC can perform spectroscopy of the emitted radiation?
A.) The amount of bubbles produced in the cocktail is proportional to the energy of the emitted radiation.
B.) The amount of heat produced in the cocktail is proportional to the energy of the emitted radiation.
C.) The size of light flashes produced in the photomultiplier tube is proportional to the energy of the emitted radiation.
D.) The size of the electronic pulses produced in the photomultiplier tube is proportional to the energy of the emitted radiation. (Correct)
5. (Explanation) In following the procedure for analyzing the waste water sample for radioisotopes, why is it important to prepare one sample that is distilled?
A.) The distilled sample ensures no radioactive gases are present and allows the determination of radioactive gas concentration.
B.) The distilled sample removes the tritium and allows the determination of non-soluble isotope concentration.
C.) The distilled sample removes all isotopes except tritium and allows the determination of tritium concentration. (Correct)
D.) The distilled sample is added to the non-distilled sample and allows the determination of total concentration.
Suggested Labs
Liquid Scintillation Counting- If a Liquid Scintillation Counter is available, demonstrate the ability to measure beta radiation with an LSC at instructor’s discretion.
ACAD References
ACAD3.2.3 Radiological Survey and Analysis Instruments
· Explain the operating characteristics and use of the following radiological survey and analysis instruments:
– Liquid scintillation counter
Module Perform Analysis of Water Samples Using Liquid Scintillation Counters (LSC)
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