Advisor(s)

Charles Wilson

Committee Member(s)

Emily Caffrey
Muhammad Maqbool

Document Type

Thesis

Date of Award

1-27-2026

Degree Name

Master of Science (MS)

School

School of Health Professions

Department

Health Professions

Abstract

Liquid Scintillation Counting (LSC) is a critical technique in operational health physics, particularly for contamination surveys. However, common, expedient sample preparation choices often introduce unpredictable levels of quench, compromising the accuracy of results. This thesis investigates the impact of common preparation variables including vial material, cap lining, solid sample matrix presence, cocktail volume, and radioactivity. The impact of these sample preparation variables were evaluated using the quench methods on two fundamentally distinct commercial LSC systems, the Perkin Elmer Tri-Carb 4910TR (employing tSIE correction) and the Hidex 600 SL (employing TDCR correction). A total of 320 samples were evaluated on each of the two LSC systems. The results confirm that preparation variables introduce measurable, system-dependent quench effects. Specifically, the tSIE method proved highly sensitive to optical parameters, or sensitivity to the sample preparation decisions which alter parameters like reflection and light transmission. This method also showed a quench sensitivity to cocktail volume within each of the vials. In contrast, the TDCR method exhibited superior performance consistency, though notably that was accompanied by a material sensitivity. The underpinnings of the method, namely the correlation to statistical behavior of electrons, was shown in the increased variation when counting samples with background radioactivity. These findings challenge the assumption of a universal "standard" preparation method and underscore the need for instrument-specific protocols, at a minimum, to ensure accurate activity measurements in high-throughput settings.

Keywords

liquid scintillation counting;quench;sample preparation;TDCR;tSIE

ProQuest Publication Number

32279089

ISBN

9798273349834

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