Improvement of the CdTe diode detectors

Recent results from the CdTe Schottky diode detectors employing a guard-ring electrode are reported. Cathode electrode, made of Pt, was separated into an active electrode(s) and a surrounding guard-ring. Typical leakage current of a device with an active area of 2 /spl times/ 2 mm/sup 2/ and 0.5 mm thickness surrounded by a guard-ring, is 7 pA and 20 pA at a bias of 100 V and 500 V, respectively, operated at 20 /spl deg/C . Spectral resolution of this device is 0.93 keV and 1.2 keV (FWHM) at 59.5 keV and 122 keV, respectively, operated at 20 /spl deg/C with a bias of 800 V. Detailed study of the characteristics of these devices working as a gamma-ray detector is presented.