The uniformity and reliability of CdTe array radiation detectors

A 90-element CdTe array radiation detector was fabricated. An average energy resolution of 6.9 keV and a count rate variation for each detector of less than 11% for 60 keV gamma -rays were achieved. Time-dependent instability was obtained with a count rate drift of less than 1% within 1 h after bias application. It is believed that these detectors can be applied to sensors of X- and gamma -ray imaging. To achieve these characteristics, a large grain crystal, above 13 mm square in this case, with homogenous distribution of crystal defects, and a reproducible fabrication process and assembly technique, which were mainly accomplished by utilizing machine controlling, were applied. Temperature cycling, humidity cycling, thermal shock, hermetic seal, mechanical shock, vibration fatigue, natural fall, and low temperature storage tests indicated no major problems with the detector under normal conditions. The mean time to failure investigated by the high temperature operating test was estimated to be more than 1*10/sup 6/ h at room temperature.<>