Pulse splitting in photon counting X-ray detectors

We performed Monte-Carlo simulations of X-ray interactions and charge transport within a photon counting CZT detector. We study various physical processes affecting the width and shape of detected pulses and find that the energy resolution depends on the pulse width variance. A major impact factor is the splitting of pulses due to the simultaneous creation of two or more charge clouds by K-fluorescence. In consequence, measured energies are underestimated dependent on the timing constants of detector and electronics.