The uniformity and reliability of CdTe-array detectors

Abstract

Fabrication of 90-element CdTe-array radiation detectors, their radiation detecting characteristics and reliability tests have been studied. To obtain detectors with uniform characteristics, the use of large-grain crystals having homogeneous defect distribution and a controlled fabrication process, such as surface preparation, contact formation and proper assembly technique, are required. An average energy resolution of 5.1 keV for 60 keV γ-rays and a count rate variation for each detector of less than 11% have been achieved. Furthermore, the detector exhibits stable operation with a count rate drift of less than 1% within one week after bias application. Environmental tests, including a temperature-cycle test and a mechanical shock test, are systematically carried out and no severe problems are found with the detector under a normal environment. A high-temperature operating test has also been performed and the mean time to failure (MTTF) is estimated to be more than 1 × 10 6 h at room temperature.