XPAD: A photons counting pixel detector for material sciences and small-animal imaging

Experiments on high-flux and high-brilliance third-generation synchrotron X-ray sources are now limited by detector performance. Photon-counting hybrid pixel detectors are being investigated as a solution to improve the dynamic range and the readout speed of the available 2D detectors. The XPAD2 is a large-surface hybrid pixel detector (68×65 mm2) with a dynamic response, which ranges from 0.01 to 106 photons/pixel/s. High-resolution data were recorded using the XPAD2. The comparison with data measured using a conventional setup shows a gain on measurement duration by a factor 20 and on dynamic range. A new generation of pixel detector (XPAD3) is presently under development. For this, a new electronic chip (the XPAD3) is designed to improve spatial resolution by using 130 μm pixels and detector efficiency by using CdTe sensors. XPAD2 is also operated with PIXSCAN, a CT scanner for mice.