Temperature-Dependent Properties of BC-412 Polyvinyl Toluene Scintillator

Christian C Cowles,Zane W Bell,Tiffany C Kaspar,Donghui Li,Eric D Sword,Richard T Kouzes,Ilia N Ivanov

doi:10.1109/tns.2022.3154645

Christian C Cowles, Zane W Bell + Show 5 more

Open Access

https://doi.org/10.1109/tns.2022.3154645

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Abstract

Polyvinyl toluene (PVT), with additives, is a widely used organic plastic scintillator that is robust and inexpensive for large-volume gamma-ray detectors. Even though PVT-based scintillators have been used for decades in many applications, some of their basic optical properties have not been fully explored. Measurements of the attenuation length, index of refraction, and scintillation light output of a specific commercial PVT-based scintillator (Saint-Gobain BC-412) as a function of temperature are presented. These properties are important to the performance of systems using PVT-based scintillators in environments subject to wide temperature variations and are being used to better model the performance of such applications.

Highlights

LARGE polyvinyl toluene (PVT) based scintillators have been deployed for decades for use in scientific research, health physics, national security, safeguards, and scrap metal screening [1] [2] [3]
Since photons must have many reflections to reach the photomultiplier tubes (PMTs) in large PVT panels, the index of refraction can change the amount of light collected as a function of temperature if the
For detector assemblies using PVT with PMTs, the PMTs introduce a temperature dependence 37% greater than that observed in the PVT scintillator material light yield, both factors having a negative slope as a function of temperature

Summary

INTRODUCTION

LARGE polyvinyl toluene (PVT) based scintillators have been deployed for decades for use in scientific research, health physics, national security, safeguards, and scrap metal screening [1] [2] [3] Some of these applications involve deployments of large PVT-based gamma-ray detectors in outside environments where they are subjected to large variations in temperature (from -40°C to 55°C), and relative humidity from desert to rain forest conditions (10-100%). There are two major PVT vendors in the U.S, Eljen Technology (Sweetwater, TX) and Saint-Gobain (Hiram, OH), and their PVT formulations are similar, with only a few percent variation in composition declared Both manufacturers indicate that their PVT-based scintillators have a 5% decrease in signal output from 20°C to 60°C, or an average of about -0.13%/°C above room temperature ( neither implies it is a linear dependence) and no change from 20°C to -60°C [6, 7].

RADIOLUMINESCE AND LIGHT YIELD

RESULTS

CONCLUSIONS