NEAR ROOM-TEMPERATURE ENERGY-DISPERSIVE DETECTORS PROCESSED ON HIGH-PURITY SILICON

Diode detectors and silicon drift chambers were processed on TOPSIL hi gh-purity silicon of resistivity 7 kOMEGA cm. Their suitability for XR F spectroscopy, when cooled to - 30-degrees-C, was evaluated. The effi ciency for different x-ray energies was calculated starting from the p rocessing parameters used in manugacturing. Spectrum measurements were made in order to establish the mechanisms causing electrical noise an d charge trapping. With an 18 mm2 active area detector it was possible to achieve an FWHM of 385 eV for the Fe-55 source 5.89 keV peak and b etter than 300 eV with detectors of 1 mm2 area. Incomplete charge coll ection was found to be due to effects on the edge of the detector acti ve area or in the implanted surface facing the radiation.