TECHNOLOGY AND PERFORMANCE OF X- AND GAMMA-RAY 32 PIXEL LINE DETECTOR BASED ON SEMI-INSULATING GAAS

František Dubecký et al

   Technology, electrical characteristics and detection performance of a recently developed and fabricated 32-pixel line array chip for detection of X- and gamma-rays named "SAMO" based on semi-insulating GaAs are reported. The chip with dimensions of 7x2.4x0.2 mm³ is mounted onto a ceramic holder. A single pixel has an active area of 2000x(120-180) mm² with a pitch of 220 mm. Current density (300 K) of a single pixel at a bias voltage of 125 V ranges between 9-50 nA/mm². The threshold voltage ranges between 150-500 V. Pulse-height spectra in both the side as well as the top irradiation modes measured using 59.5 keV and 122 keV gamma-sources are demonstrated. The best detection performance observed with SAMO pixel line detector for detection of 122 keV gamma rays at 300 K in the side irradiation reached a charge collection efficiency 85 %, relative energy resolution in HWHM 4 %, and detection efficiency in the photopeak 50 %.

Keywords: radiation detector, semiconductor, GaAs, semi-insulating, pixel line

[full-paper]