Analysis of the output signal waveform and performances of semi-insulating GaAs particle detecors

This paper presents an extensive analysis of the signals at the output of a charge sensitive amplifier delivered by a semi-insulating liquid-encapsulated Czochralski grown GaAs particle detector, irradiated with 5.48 MeV alpha particles. When the detector is operated below full depletion the shape of the output signal can be explained by the equivalent circuit of the detector itself, while above full depletion it is affected only by trapping-detrapping processes and it is well interpreted in terms of trapping and detrapping times of deep level traps present in the materials. Spectral lines of alpha particles from an 241Am source have shown a resolution of 1.1% at room temperature.