Indirect X-ray photon-counting image sensor with 27T pixel and 15e−rms accurate threshold

In X-ray imaging, as in other imaging domains, the ultimate sensitivity and signal-to-noise ratio are obtained when each incoming photon is counted - the so-called quantum limit. Present state-of-the-art digital radiography is largely “charge integration” based, which results in a read noise that is composed of the quantum-limited photon shot noise, but also of electronic read noise and excess noise due to the non-reproducible charge packet sizes per absorbed X-ray photon.