Monte Carlo simulator of the charge signal induced by external radiation on semi-insulating GaAs detectors

We present a Monte Carlo simulator of the charge signal induced by external radiation on a semi-insulating GaAs detector. The relative contribution to the charge signal of fast and slow time components as well as the time constant of the slow component are studied as a function of the applied voltage. The collected charge efficiency is evaluated in terms of relevant time scales. Calculations compare well with experimental results.