Improved spectroscopic performance in compound semiconductor detectors for high rate X-ray and gamma-ray imaging applications: A novel depth of interaction correction technique

摘要

In this paper results are presented for a novel charge loss correction algorithm that exploits the process of charge induction within compound semiconductor detectors. By detecting the residual induced signals in the pixels neighbouring an event, it is possible to correct for variation in the charge collection efficiency that occurs when high energy photons deposit charge at different depths in the detector. Results from 500 mu m pitch pixel detectors produced from both GaAs: Cr and high-flux-capable CdZnTe material readout using the STFC's PIXIE ASIC are used to demonstrate the correction process across two different detector materials. The application of this depth of interaction correction results in a significant improvement in the FWHM of the 59.5 keV gamma-ray photopeak in a 0.5 mm thick GaAs:Cr sensor from 14 keV to 4.7 keV. The application of the correction at the higher energy 122 keV gamma-ray photopeak in a 2 mm thick CdZnTe detector also demonstrated an improvement from 4.0 keV to 2.7 keV.