Scintillation Properties of Undoped CsI and CsI Doped With CsBr

The light output, energy resolution, and nonproportionality characteristics were measured for undoped CsI and several samples of CsI with different doping by CsBr. A correlation between nonproportionality of the light yield and the intrinsic energy resolution was confirmed. Contrary to previously published results the light yield of the tested samples was found to be degraded with increasing bromine concentration. The inspection of light pulse shapes was done by the single photon coincidence method. Decay times of the scintillation pulse were measured for undoped and bromine doped crystals, showing the main scintillation in tens of nanoseconds range.