A High Rate Amplifier-Digitizer System for Liquid Argon Calorimeters

A low cost charge amplifier for a liquid argon photon detector and a new method for pulse height analysis are described. This scheme is suitable for high energy photon detection with high counting rate. Samples of preamplifier output are taken just before and just after the arrival of the charge from the detector. The difference of these samples provides a stable pedestal and rejects low frequency noise. Short two-pulse resolving time (≃200ns) is achieved.