Room-Temperature X-ray response of cadmium-zinc-Telluride pixel detectors grown by the vertical Bridgman technique

In this work, the spectroscopic performances of new cadmium-zinc-Telluride (CZT) pixel detectors recently developed at IMEM-CNR of Parma (Italy) are presented. Sub-millimetre arrays with pixel pitch less than 500μm, based on boron oxide encapsulated vertical Bridgman grown CZT crystals, were fabricated. Excellent room-Temperature performance characterizes the detectors even at high-bias-voltage operation (9000Vcm-1), with energy resolutions (FWHM) of 4% (0.9keV), 1.7% (1keV) and 1.3% (1.6keV) at 22.1, 59.5 and 122.1keV, respectively. Charge-sharing investigations were performed with both uncollimated and collimated synchrotron X-ray beams with particular attention to the mitigation of the charge losses at the inter-pixel gap region. High-rate measurements demonstrated the absence of high-flux radiation-induced polarization phenomena up to 2 × 106photonsmm-2s-1. These activities are in the framework of an international collaboration on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging.