SUMMARY

Organic scintillators are a powerful tool in the detection of fast neutrons through a process known as pulse shape discrimination (PSD). In industrial applications, over-doped (around 20wt.%) plastic-based scintillators, like PVT, are a common choice due to their ease of handling and relatively cheap price when compared to liquid or crystalline-based scintillators. However, the over-doping leads to negative long-term properties like instability of the dopant or hazing. An alternative may be polysiloxane-based scintillators. These scintillators only require about 4%wt. of dopant to have similar detector performance to PVT based scintillators. This work details the results of custom polysiloxane-based scintillators fabricated and characterized jointly by Georgia Tech and Colorado School of Mines for both figure of merit (FoM) and light yield (LY) optimization. These custom scintillators were able to outperform EJ-299 industry standards for solid PSD-capable scintillators manufactured by Eljen in FoM with comparable LY. The polysiloxane scintillators also have been tested for temperature-dependent properties which, showed an improved FoM (around 10%) and only a slight decrease in LY (around 3%) at 50°C.