Direct detection of X-rays is one of the key components of Hybrid Photon Counting (HPC) technology. It is achieved by direct conversion of X-ray photons to an electrical charge that can be electronically detected and processed. This conversion takes place in the sensor pixel component of a hybrid pixel. In the sensor pixel, absorption of X-ray photons leads to the generation of electron-hole pairs and a charge proportional to the X-ray energy. The detection and processing of the charge occurs in the hybrid pixel’s readout component.
In a direct conversion X-ray detector, the charge generated by the sensor pixel is captured in an electrical field. This keeps the spread of the signal across the detector to a minimum and maximizes spatial resolution. Also, the loss of signal is minimized because of trapping in an electrical field. This produces the high sensitivity and quantum efficiency found in direct conversion detectors.
DECTRIS HPC detectors’ readout pixels are specifically designed for direct detection of X-rays.