Modelling by an analytical function of a pixellized CdTe photoconductor response

We are studying the characteristics of a pixellized CdTe detector for high energy imaging applications. We model analytically the spatial response of this kind of detector in order to simulate the image it provides. Firstly, we simulate the spatial distribution of the energy deposition (PSF) in the bulk material (not pixellized) with the Monte-Carlo codes MCNP4.2 and CYLTRAN. Secondly, we calculate the Line Spread Function (LSF, which is deduced from the calculated PSF by the Abel transform), the pixellization effects and the Modulation Transfer Function (MTF). Then we model the LSF with analytical peak functions. We verify simultaneously that there is a good consistency between both modelled and Monte Carlo calculated curves for the LSF, pixellized LSF and MTF. Finally, an image is simulated by the analytical response of the detector.