MODELING 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 re sponse of this kind of detector in order to simulate the image it prov ides. Firstly, we simulate the spatial distribution of the energy depo sition (PSF) in the bulk material (not pixellized) with the Monte-Carl o codes MCNP4.2 and CYLTRAN. Secondly, we calculate the Line Spread Fu nction (LSF, which is deduced from the calculated PSF by the Abel tran sform), the pixellization effects and the Modulation Transfer Function (MTF). Then we model the LSF with analytical peak functions. We verif y simultaneously that there is a good consistency between both modelle d and Monte Carlo calculated curves for the LSF, pixellized LSF and MT F. Finally, an image is simulated by the analytical response of the de tector.