X-ray Detection using Single Photon Avalanche Diodes

We present the first reported use of a CMOS Single Photon Avalanche Diode (SPAD) arrays for the detection of high energy photons (X-rays), utilizing a 3D-stacked backside illuminated (BSI) SPAD image sensor, and cabinet biological X-ray irradiator. We detected photon peak energies from 30 to 120 keV, and an increase in SPAD bias voltage results in higher relative average counts per pixel. Furthermore, after an absorbed radiation dose of 3.75 Mrad, the difference in DCR was found to not be statistically significant, with a calculated two-sided P-value of 0.787. This unveils new applications in X-ray detection.