Simulation of signal generation processes in semiconductor sensor layers for Medipix1 and 2

X-ray imaging with high spatial resolution and high dynamic range is desirable for many applications. The Medipix1 and Medipix2 detectors have a variable semiconductor conversion layer with a pixel size of (170 μm)2 or (55 μm)2, respectively. The spatial resolution is limited by the amount and distance of secondary electrons created per photon. The EGS4-based Monte Carlo simulation (ROSI) is used to calculate the spatial spread of the single photon energy deposition for varying X-ray energies for Si, GaAs and CdTe.