Study of Silicon Pixel Sensors for Synchrotron Radiation Detection

Abstract

Hybrid pixel single-photon-counting detectors have been successfully employed and widely used in Synchrotron radiation X-ray detection. In this paper, the silicon pixel sensors for single X-ray photon detection, which operate in full-depletion mode have been studied. The pixel sensors were fabricated on 4-inch, N type, 320μm thick, high-resistivity silicon wafers. The pixel sensors has a p+-in-n structure with varies of pixel size and gap size including guard-ring structures. Later, the pixel sensor was wire bonded to the ASIC circuits and tested for the performance of X-ray response in the synchrotron beam line (BSRF, 1W2B). From the S-curve scan, we could get the energy resolution and the linear properties between input energy and the equivalent generator amplitude. The pixel sensors we fabricated have a good energy linear and high count rate depending on the ASIC readout circuit. We get the 20% energy resolution above 10 keV photon energy via wire bonding. The energy resolution would get better if we bond the sensor via indium ball for the smaller stray capacitance.