A Detection Module for Hard X-ray Spectroscopy Based on an In-Schottky CdTe Detector

We developed a specifically designed integrated detection module based on a In-Schottky CdTe detector for X-ray spectroscopy. The CdTe detector features an Pt ohmic contact (entrance window) and a In Schottky contact on the opposite side. The detector active area is 4 mm × 4 mm and the detector thickness is 1 mm. The detector is sealed in a T08 case with 100 micrometer Al window and features an output capacitance of 2 pF. The detection module is made of aluminium and is 54 mm × 54 mm× 198 mm and contains the detector, the biasing system and the frontend electronics. The biasing systems allows automatic switching of the detector high voltage to minimize polarization effects of CdTe during long acquisition times. A full characterization of the noise performance and of hole tailing as a function of detector bias voltage and of the shaping time has been carried out and will be discussed. The measured resolution at the 59.5 keV gamma-ray line is 1.47 keV FWHM, slightly higher than expected (about 1 keV FWHM) due to higher stray capacitance on the input node. The developed detection module is well suited for a number of demanding applications, with a useful energy range from few keV (e.g. Mn kalpha line) to several hundreds of keV. Relevant examples are shown and discussed.