STUDY OF A CDTE MULTIPIXEL SPECTROMETER FOR X-RAYS AND GAMMA-RAYS

The performance of a prototype CdTe linear multipixel detector in the arrangement with the collecting field orthogonal to the incoming radia tion (PTF configuration) is reported. This detector was conceived to b e employed as the basic element to realise both two-dimensional and li near position sensitive spectrometers with a large number of pixels fo r hard X- and soft gamma-rays. The prototype has been produced from a single CdTe crystal of 10 X 10 X 2 mm(3) using strips technology and i s geometrically equivalent to a linear array of five microdetectors of 2 X 2 x 10 mm(3) with the electrodes deposited on the 2 X 10 mm(2) si des, The active area of each pixel is about 2 x 2 mm(2). After the ele ctrical characterisation of the detector, several tests have been perf ormed by radiating the detector with standard sources. Scanning the de tector with a Co-57 source over the pixels has shown the uniformity of spatial response and has allowed the measurement of the spatial resol ution of the array. In order to evaluate the spectroscopic capability further tests using sources with energy between 10 and similar to 400 keV, moved along the anode-cathode direction, have been performed. The first results have demonstrated that the multipixel CdTe crystal acts as a linear position sensitive spectrometer made of 5 PTF microcrysta l at least up to a few hundreds keV.