A Cdte Real Time X-Ray Imaging Sensor and System

Abstract

A real time X-ray imaging sensor consisting of p-type CdTe pixel detectors with barrier type In front contacts (anode) and Pt pixel contacts (cathode) has been developed and tested. The 5 x 5 cm 2 sensor area is covered with four CdTe pixel detectors each bump bonded to two CMOS readout circuits and mounted side by side to a support board. Each CMOS has 127 x 253 pixels with a pitch of 100 mum. The sensor is operated in the charge integration mode. User selective digital video frame output rates up to 60 fps are possible. A detector bias voltage cycle which brings the voltage instantaneously to zero at a certain interval is applied to eliminate the effect of polarization. Real time image calibration is applied to compensate for leakage current variation and CMOS mismatch. The CdTe pixelization process and the sensor design and operation are described. Experimental results of the MTF, SNR and DQE are presented and X-ray images of printed circuit boards are shown. (C) 2004 Elsevier B.V. All rights reserved.