A high frame rate pixel readout chip design for synchrotron radiation applications

A hybrid pixel detector working in the single photon counting mode was designed for the High Energy Photon Source (HEPS) in China. Aiming for diffraction and protein crystallography applications, the pixel readout chip works in single photon counting mode in each pixel. It contains an array of 104 × 72 pixels with a pixel size of 150μm×150 μm, each owning a counting depth of 20bits. Different from the conventional readout structure based on the pseudo-random counter, an independent shift register chain was inserted, separated with the counter. Therefore this design allows high frame rate counting and data transfer simultaneously. The chip measurement showed 94 e- equivalent noise and non-uniformity less than 55 e-after threshold equalization. All functions were proved to be normal at a frame rate of 1.2 kHz with a negligible dead-time, which are greatly improved compared with the existing pixel system.