Design, construction and first operation of the large CsI calorimeter for the BABAR detector at the PEP-II storage rings

The design and construction of the BaBar electromagnetic calorimeter are reviewed. Recent results on the expected sensitivity of the CsI(Tl) to radiation damage are discussed. The performance of the calorimeter in the first PEP-II run is presented. Particular emphasis is placed on operational experience and the measured degradation due to radiation damage. Correlation of radiation damage with the dose recorded in a novel large-scale array of radiation sensitive FETs are presented. The consequences for the long-term performance of a CsI(Tl) calorimeter operating in a high background environment are discussed