Measurements Of Ultra-Fast Single Photon Counting Chip With Energy Window And 75 Mu M Pixel Pitch With Si And Cdte Detectors

Single photon counting pixel detectors become increasingly popular in various 2-D X-ray imaging techniques and scientific experiments mainly in solid state physics, material science and medicine. This paper presents architecture and measurement results of the UFXC32k chip designed in a CMOS 130 nm process. The chip consists of about 50 million transistors and has an area of 9.64 mm x 20.15 mm. The core of the IC is a matrix of 128 x 256 pixels of 75 mu m pitch. Each pixel contains a CSA, a shaper with tunable gain, two discriminators with correction circuits and two 14-bit ripple counters operating in a normal mode (with energy window), a long counter mode (one 28-bit counter) and a zero-dead time mode. Gain and noise performance were verified with X-ray radiation and with the chip connected to Si (320 mu m thick) and CdTe (750 mu m thick) sensors.