Characterization of CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors for X-ray science

Abstract

Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded\npixel-by-pixel to an underlying readout chip. This approach allows both the\nsensor and the custom pixel electronics to be tailored independently to best\nmatch the x-ray imaging requirements. Here we present characterizations of CdTe\nsensors hybridized with two different charge-integrating readout chips, the\nKeck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our\nlaboratory. The charge-integrating architecture of each of these PADs extends\nthe instantaneous counting rate by many orders of magnitude beyond that\nobtainable with photon counting architectures. The Keck PAD chip consists of\nrapid, 8-frame, in-pixel storage elements with framing periods $<$150 ns. The\nsecond detector, the MM-PAD, has an extended dynamic range by utilizing an\nin-pixel overflow counter coupled with charge removal circuitry activated at\neach overflow. This allows the recording of signals from the single-photon\nlevel to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both\ndetector chips consist of a 128$\\times$128 pixel array with (150 $\\mu$m)$^2$\npixels.\n