Integrated readout electronics for the PbWO{sub 4} photon spectrometer

The PbWO{sub 4} calorimeter of the ALICE detector is designed to detect the prompt photons to provide direct information on the partonic, early phases of the heavy-ion interaction. The goal is to measure all the photons over a large enough solid angle to reconstruct both {pi}{sup 0}`s and {eta}`s. A proposed readout system for the ALICE PbWO{sub 4} photon spectrometer is presented. In one proposed implementation, light will be detected from each end of the crystals by PIN photodiodes and this signal will be amplified by charge-sensitive amplifiers. The 73,728 channel readout system will accept the preamplifier signals and deliver digitized data to the data collection modules. A readout board will consist of 8-channel, custom front-end chips which form energy and timing signals, and board-level control and communication circuits. Many of the subcircuits proposed for this spectrometer have been developed for use in other applications. The performance of these circuits is shown.