Correction of the charge sharing in photon-counting pixel detector data

Abstract

Although photon-counting pixel detector arrays provide energy discrimination capabilities, their energy resolution is limited by the diffusion of the photoelectric charge between neighboring pixels. This effect often referred to as charge sharing induces a low-energy tail in the measured spectra and is particularly significant for small pixel sizes. In order to correct this effect, an iterative deconvolution method has been developed and applied to data collected with the Medipix2 photon-counting chip. The obtained spectra are corrected from charge sharing and moreover show a better energy resolution than the raw spectra. For instance the Kα (22.1 keV) and Kβ (25 keV) emission lines of a 109Cd source are reconstructed as two well-separated peaks. The principle of the method will be exposed. Various results obtained with synchrotron beams, X-ray tubes and radioactive sources will be shown.