XPAD: A Photons Counting Pixel Detector for Material Sciences and Small Animal imaging

A paraître dans NIMInternational audienceExperiments on high flux and high brilliance 3rd 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 x 65 mm$^2$) with a dynamic response which ranges from 0.01 photons/pixel/s up to 10$^6$ photons/pixel/s. High resolution data have been 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) has been designed to improve spatial resolution by using 130 $\mu$m pixels and detector efficiency by using CdTe sensors. XPAD2 is also operated with PIXSCAN, a CT-scanner for mice