Gamma radiation dose rate effects on a polymer scintillator containing a large Stokes shift dye, 3-hydroxyflavone

Samples of a proprietary polystyrene scintillator doped with p-terphenyl and a large Stokes shift dye, 3-hydroxyflavone, were gamma irradiated to 10 Mrads in a Co ⁶⁰ source at various dose rates ranging from 1.5 to 0.0023 Mrads/h, while exposed to air during and after irradiation. No recovery in light output was observed, possibly due to lower PMT sensitivity. The scintillator light output after irradiation decreased with decreasing log(dose rate) of irradiation. The large Stokes shift fluor thus had not enhanced radiation stability with respect to the dose rate. The log(dose rate) relationship can be used though to estimate the light output at lower dose rates of irradiation.