Radiation damage in undoped CsI and CsI (Tl)

Radiation damage in undoped CsI and CsI(Tl) crystals using /sup 60/Co gamma radiation for doses up to approximately 4.2*10/sup 6/ has been studied. Samples from various manufacturers were measured, ranging in size from 2.54-cm-long cylinders to a 30-cm-long block. Measurements were made on the change in optical transmission and scintillation light output as a function of dose. Although some samples showed a small change in transmission, a significant change in light output was observed for all samples. Recovery from damage was also studied as a function of time and exposure to UV light. A short-lived phosphorescence was observed in undoped CsI, similar to the phosphorescence seen in CsI(Tl).>