The MM-PAD-2.1: A Wide-Dynamic-Range Detector For High-Energy X-ray Imaging

We have fabricated 128×128 pixel readout ASICs for the MM-PAD-2.1, a wide-dynamic-range photon-integrating detector intended for high-energy x-ray imaging (>20 keV). Design specifications include a signal-to-noise ratio of 10 for measurement of a single 20-keV photon, a maximum measureable signal of 10
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20-keV photons/pixel/frame, and the ability to accurately measure sustained photon rates of ≥ 10
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20-keV photons/pixel/s. The pixel pitch is 150 µm, resulting in an active area of 19.2 mm × 19.2 mm per single-chip module. ASICs have been bonded to both Si and CdTe sensors. Detector control firmware has been designed that allows for selective readout of a 128×128 pixel area at 9 kHz, or readout of the full array at 1.5 kHz. First results from characterization of the full-scale chip are reported.