A novel architecture for DAQ in multi-channel, large volume, long drift Liquid Argon TPC

Abstract

Recently a large interest has been shown for multi-ton Liquid Argon Time-Projection-Chambers (LAr-TPC). The physics issues are very challenging, but the technical problem of long drifts and adequately long life-time of free electrons are not solved at all so far. Also one should take into account the extremely large number of channels required for such large volumes. In this paper we propose an architecture for DAQ that is based on recent developments in consumer electronics that made available, at a quite interesting price, components aimed to high-resolution delta-sigma conversion. This type of ADC is not at all popular in HEP experiments where normally signals related to events, well defined in time (triggered), should be converted and recorded. In the LAr-TPC however we have to deal rather with waveforms that should be converted and recorded continuously, that is the paramount case of delta-sigma ADC application.