Detection of soft X-rays using semi-insulating GaAs detector

This work deals with the performance of thin semi-insulating GaAs-based detectors of ionizing radiation DC-coupled to the low noise readout electronics. Fabricated detector have square shape Ti/Pt/Au Schottky blocking contact with dimension of 0.5 mm and full area AuGeNi eutectic alloy quasi-ohmic contact on the opposite site. The current-voltage characteristic and ²⁴¹Am pulse-height spectra of the detectors were measured and evaluated. The best energy resolution of 6.7 % for 59.5 keV gamma photons was achieved at lowered temperature of 255 K. The detector and the first stage of preamplifier (JFET) was cooled using one stage Peltier cooler.