Temperature dependence of CsI (T1) absolute scintillation yield

A cubic CsI(TI) crystal of 0.8 cm on a side was mounted on a 1 x 1 cm square photodiode to measure the absolute scintillation yield of CsI(TI) between - 100 and + 50°C. The room temperature yield was measured to be 64,800 + 3,200 photons/MeV. The maximum yield was observed to occur at about -35°C, approximately 6% above the room temperature yield. The yield was observed to decrease monotonically above and below this maximum. At - 100 and + 50°C the yield was measured to be about 64% and 95% of the room temperature yield, respectively. Over the range of - 55 to + 50°C the scintillation yield was observed to remain within +6% of the room temperature yield. The temperature dependence of scintillation decay time, scintillation emission spectrum, and wavelengthdependent photodiode quantum efficiency were considered.