A 7.2inch 5.5Mpixel 600mW SPAD X-Ray Detector with 116.7 dB Dynamic Range

This paper presents the first 7.2-inch wafer-level SPAD X-ray detector for radiography and industrial applications. A digital SPAD pixel achieves high SNR at low dose and wide DR. Large power consumption of the photon counting at high dose is effectively mitigated by using an extrapolation method, and the overflow flag of the photon counter is flexibly selected for further power reduction. High throughput is achieved with a pipelined readout chain of the pixel output. Implemented in a 65nm CMOS process, the detector consists of $3296\times 1680$ pixels with a pixel pitch of $49.5\mu \mathrm{m}$, corresponding to an area of $16.5\times 8.9\text{cm}^{2}$, and consumes only 600mW at 13frames/s, while achieving a DR of 116.7dB. The global shutter operation delivers high-quality image without motion artifacts. Excellent radiation hardness of up to 10,000Gy is also achieved.