Improved Spectrometer Performance of Cadmium Selenide Room Temperature Gamma-Ray Detector

The surface preparation technology of CdSe crystals used for room temperature gamma-ray detection has been studied. X-ray fluorescense analysis of the surface of the crystal exposed to the Br-methanol etchant revealed the production of CdBr2 compound as a result of the crystaletchant reaction. The CdBr2 "poisoning" causes high surface leakage currents increasing significantly the electronic noise of the device. A modified etching process has been developed in present work allowing to reduce greatly the surface leakage. Prominent reduction in the noise threshold with a simultaneous improvement of the energy resolution of CdSe detectors is reported.