On technology and performance of SAMO:: X- and γ-ray 32-pixel line detector based on semi-insulating GaAs and InP

Electrical characteristics and detection performance of recently developed and fabricated 32-pixel line array chip for detection of X- and gamma -rays named "SAMO" based on semi-insulating GaAs and InP are reported. The chip with dimensions of 7 x 2.4 x (0.2-0.3) mm(3) is mounted on a ceramic holder. Single pixel has an active area of 2000 x (120-180) mum(2) with pitch of 220 mum. Current density of GaAs-based single pixel at a bias voltage of 120 V ranges between 15 and 60nA/mm(2). The threshold voltage ranges between 150 and 500V, Pulse-height spectra in both, side as well as top irradiation modes measured using 59.5V and 122keV gamma -sources are demonstrated. The best detection performance observed with GaAs-based SAMO line detector reached charge collection efficiency of 85%, relative energy resolution in HWHM 4%, and detection efficiency in the photopeak 52% (122keV, 300 K, the side irradiation). Preliminary results obtained with InP-based SAMO line detector are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.