Optimized mounting of a polyethylene naphthalate scintillation material in a radiation detector

•Optimum mounting conditions in a radiation detector for PEN are discussed.•We determined light yields for various optical couplings and substrate surfaces.•PEN is sensitive to the optical coupling due to its high refractive index.•We simultaneously assessed the extent of radioactive impurities in PEN as background sources.•The radioactive impurities in PEN are equivalent to the environmental background level.

Polyethylene naphthalate (PEN) has great potential as a scintillation material for radiation detection. Here the optimum mounting conditions to maximize the light collection efficiency from PEN in a radiation detector are discussed. To this end, we have determined light yields emitted from irradiated PEN for various optical couplings between the substrate and the photodetector, and for various substrate surface treatments. The results demonstrate that light extraction from PEN is more sensitive to the optical couplings due to its high refractive index. We also assessed the extent of radioactive impurities in PEN as background sources and found that the impurities are equivalent to the environmental background level.