Onset of Fogging and Degradation in Polyvinyl Toluene-Based Scintillators

Abstract

Plastic-based gamma-ray detector materials such as polyvinyl toluene (PVT) occasionally suffer from loss of optical light transmission due to internal defects or “fogging” when exposed to some environmental conditions over time. Fogging results in reduced scintillation light propagated to the photomultiplier tube for collection. Investigations of the physical cause of these defects and their associated environmental conditions are ongoing. The goal of this article was to characterize the signs and effects of fogging over a simulated 22-year lifespan of the PVT in outdoor environments. Two potential mitigation methods were also evaluated, and one successfully mitigated the phenomena.