ABSTRACT
Despite their many anticipated advantages, photon counting detectors suffer from effects that are not known from conventional, energy integrating devices. These effects arise from the discretization of photon events and result in non-linear, shift-variant behavior. In this chapter, I will first introduce the reader to charge sharing and characteristic x-rays as the main sources of such an undesired behavior. Next, I will explain why methods from linear systems theory fail to adequately describe most state-of-the-art photon counting detectors. Finally, I will present and discuss how concepts of advanced chip engineering are able to restore shift-invariance. Prospectively, these techniques have the potential to yield photon counting detectors that can exploit their full potential by offering noise properties close to actual Poisson statistics.
