Simulation of one-dimensionally polarized X-ray semiconductor detectors

A pixelated X-ray semiconductor detector (="direct converter") is studied which contains an inhomogeneous electric field parallel to the depth axis caused by different concentrations of ionized dopants. X-ray energy depositions and charge movements within the detector are modeled in Monte-Carlo simulations giving access to a statistical analysis of electron drift times and current pulse widths for various degrees of static polarization. Charges induced on the pixel electrodes and pulse heights are evaluated and put to histograms of spectral detector responses and pulse height spectra, respectively, considering energy measurements before and after electronic pulse shaping. For n-doped semiconductors, the detector performance degrades due to pulse broadening. In contrast, a moderate p-doping can improve the detector performance in terms of shorter electron pulses, as long as the detector is not limited by dynamic polarization.