High Resolution Liquid Argon Total-Absorption Detectors: Electronic Noise and Electrode Configuration

Ionization chambers in which almost all of the energy released in electromagnetic showers is absorbed in liquid argon are considered. Electronic noise is determined as a function of the electrode configuration. It is shown that in a multiple-plate ionization chamber the optimum interelectrode gap is determined as one third of the product of the electron drift velocity and the event resolving time. The lower limit for electronic noise is determined only by the chamber volume, electron drift velocity, event resolving time and the unity-gain frequency of the field-effect transistor. This limit is approximately the same for ionization chambers with one or more large gaps where the electron drift time is much longer than the event resolving time.