Task 3: Radiation Damage Studies on CsI(Tl) Crystals.

(Reidy, student)

We have moved our Cs-137 radiation source to the HEP experimental area and are preparing to initiate low-dose long-term irradiations on large CsI(Tl)crystals as soon as we get them. Uniform dose rates equivalent to 5-10 krad/yr will be used with continuous monitoring of the crystal light output and resolution. The crystal (or crystals since the irradiation field can accommodate a number of crystals) will be placed in an environment that will approximate the environment of the BaBar calorimeter. Electronics modules can also be irradiated in this configuration. In addition, high dose rate measurements (1-100 krad/hr with a Co-60 source) on small crystals and perhaps one large crystal will be done as comparison measurements with other groups and to correlate with the low dose studies. The low dose measurements require us to tie up some electronics and a DAQ sytem for a year or more - equipment which we don't have to spare for that period of time.