New readout electronics for the Venus liquid argon calorimeter at TRISTAN

New readout electronics for the Venus end-cap liquid argon calorimeter was developed and has been operating for over a year at TRISTAN. The entire system was designed in such a way that the gain of each readout channel could be calibrated to better than 1%. The system consists of 3840 channels of readout electronics. It uses hybrid charge-sensitive amplifiers located in the 7.5-kG magnetic field and TKO-bus-based electronics which consists of CR-(RC)/sup 4/ filters, sample-and-hold circuits and 14-bit ADCs (analog digital converters). The energy resolution sigma /sub E//E for an electromagnetic shower has been found to be 3.5% at 28 GeV without any channel-by-channel gain calibration. The resolution was also determined to be sigma E/E=1.4%+11.3%/ square root E(GeV) from a large sample of 28-GeV Bhabha events and a small sample of e/sup +/e/sup -/ to e/sup +/e/sup -/ gamma events.<
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