Exploring Variations in Fast Curing Plastic Scintillator Formulations: Optimizing TPO and Evaluating the Effects of High-Z Loading and Novel Waveshifters
Organic plastic scintillators are widely used due to their relative low cost, physical robustness, and fast timing properties, but typically provide lower light yields and photon sensitivity compared to other alternatives. Photocuring novel plastics offers a viable method for producing fast curing plastic scintillators. The current formulations include an acrylic polymer base and utilize diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as the photo-initiator for polymerization; however at higher concentrations of TPO may adversely affect scintillator light output. The present research refined the optimal TPO concentrations that fully cure these acrylic-base scintillators and maximize light production to 0.4-0.5% by weight. Additionally, this research examined whether the use of high-Z loading to improve photon sensitivity impairs the pulse shape discrimination of the fast cured plastic scintillators, and confirmed that loadings of up to 10% by weight of triphenyl bismuth improved photon sensitivity and also preserved pulse shape discrimination. Finally, alternative waveshifters were also evaluated; however, Exalite 416 was determined as the optimal waveshifter for future use
