Energy calibration of photon counting detectors using a single monochromatic source

Abstract

In recent years, spectral X-ray imaging using photon counting detectors (PCDs) becomes a hot topic in the field. For a PCD, each individual incident photon with different energies is analyzed and assigned to different energy channels according to pre-set thresholds respectively. Thus, the data from an energy channel carry spectral information. Because of the influence of pulse pileup, charge sharing and other physical effects, energy calibration of PCDs is a piece of challenging work. Various energy calibration methods of PCDs have been researched. Most of them demand extensive work with additional sources or equipments. In this work, we propose a novel approach for energy calibration by using only one monochromatic source. We use iterative optimization method to fully excavate and utilize the data. The method requires fewer experiments than other common-used calibration methods. Moreover, the charge sharing effect is implicitly taken into account in this method which is an important factor in the calibration of pixel detectors. We validated our method with radioactive sources. The resulting energy spectrum matched well as expected.