Investigations and corrections of the light output uniformity of CsI(Tl) crystals

The dependencies of the light output response of CsI(TI) crystals for various charged particle beams are investigated. Measurements were performed using 5.5 MeV Am-241 alpha particles, 220 MeV alpha and 110 MeV deuteron beams from the K500 Cyclotron at Texas A&M University, and p, H-2, He-3, Li-6, and Be-7 beams from the Coupled Cyclotron Facility at Michigan State University. These measurements reveal a clear correlation between the non-uniformities observed in the same crystal for the various beams. Particle dependent global corrections were applied, resulting in final light output uniformities of the order of 0.1%. Annealed and non-annealed CsI(TI) detectors and crystals with different thalium dopings are compared to determine whether annealing reduces the local variations in the light output. No significant correlation with the crystal fabrication process is observed. (C) 2004 Elsevier B.V. All rights reserved.