Preliminary tests of semi-insulating GaAs radiation detectors coupled to the multichannel ASIC DX64 readout chip

This work deals with the performance of semi-insulating GaAs-based detectors of ionizing radiation DC-coupled to the multichannel readout chip ASIC DX64. Fabricated detectors have circular Ti/Pt/Au Schottky blocking contact with four different diameters and full area AuGeNi eutectic alloy quasi-ohmic contact on the opposite site. The current-voltage characteristics and ²⁴¹Am pulse-height spectra of the detectors were measured and evaluated. It is demonstrated that the system allows operation in single photon counting regime applicable in new generation "quantum" and digital X-ray imaging and foreseen energy separation so called "colour" imaging applications.