Evaluation of the charge-sharing effects on spot intensity in XRD setup using photon-counting pixel detectors

In this study we examine how charge loss due to charge sharing in photon counting pixel detectors affects the recording of spot intensity in an X-ray Diffraction (XRD) setup. In the photon counting configuration the charge from photons that are absorbed at the boarder of a pixel will be shared between two pixels. If the threshold is high enough these photons will not be counted. However, if the threshold is low enough these photons will be counted twice. In an XRD setup the intensity and position of various spots should be recorded. Thus, the intensity measure will be affected by the setting of the threshold. In this study we used a system level Monte Carlo simulator to evaluate the variations in the intensity signals for different threshold settings and spot sizes. The simulated setup included an 8keV monochromatic source (providing a Gaussian shaped spot) and the MEDIPIX2 photon counting pixel detector (55 µm x 55 µm pixel size with 300µm silicon) at various detector biases. Our study shows that the charge sharing distortion can be compensated by numerical post processing and high resolution in both charge (charge distribution?) and position can be achieved.