Characterization of a module with pixelated CdTe detectors for possible PET, PEM and compton camera applications

We present the measurement of the energy resolution and the impact of charge sharing for a pixel CdTe detector. This detector will be used in a novel conceptual design for diagnostic systems in the field of nuclear medicine such as positron emission tomography (PET), positron emission mammography (PEM) and Compton camera. The detector dimensions are 10 mm × 10 mm × 2 mm and with a pixel pitch of 1 mm × 1 mm. The pixel CdTe detector is a Schottky diode and it was tested at a bias of -1000 V. The VATAGP7.1 frontend ASIC was used for the readout of the pixel detector and the corresponding single channel electronic noise was found to be σ < 2 keV for all the pixels. We have achieved an energy resolution, FWHM/E_peak, of 7.1%, 4.5% and 0.98% for 59.5, 122 and 511 keV respectively. The study of the charge sharing shows that 16% of the events deposit part of their energy in the adjacent pixel