Characterization of thin back-to-back CdTe detectors

Thin CdTe detectors (3 x 5 mm(2) electrode area, 0.5 and 0.8 mm thick), mou nted in back-to-back configuration with common anode have been characterize d. This configuration allows one to double the useful absorbing thickness i n the classical planar parallel field (PPF) irradiation geometry and to dou ble the sensitive area in the planar transverse field (PTF) geometry, while maintaining the same interelectrode distance (0.5 or 0.8 mm) and one elect ronic chain as for single detectors. The tests performed aim at understandi ng the effects on the spectroscopic performance of various interelectrode d istances and in particular of the chemical and mechanical treatments used t o make thin detectors. A narrow photon beam, 10-150 keV in energy, obtained using a 20-mm-thick tungsten collimator, was employed. The results obtaine d, compared with previous measurements on various thicknesses devices, indi cate that the optimum single detector thickness is 1 mm.