Monte Carlo simulation on single photon counting charge coupled device

The Monte Carlo models for studying the quantum efficiency and the split pixel event of PI-LCX: 1300 charge coupled device (CCD) were set up. The X-ray transport in the CCD chips was simulated using the Monte Carlo code Geant4 in the energy range of 0.5-30.0 keV. The energy deposit spectra of X-ray in CCD chips were investigated, the subsequent quantum efficiency obtained is in good agreement with that offered by the manufacturer. Simulation results show that the efficiency increase with increasing the thickness of the Si layer and this effect is not obvious for high energy X-rays. The deposited energy spread in multi-pixels was studied. It shows that the surrounding pixels split the incident photon energy by deriving from the characteristic and Rayleigh scattering X-rays, which are generated in the central pixel but escape from it. In the range of 5-30 keV, the energy deposit efficiency and the effect of the multi-pixel pollution decrease as the X-ray energy increases. (authors)