Research On The Effects Of Charge Transfer Efficiency On X-Ray Energy Spectra Taken With Ccds

The incident low-energy X-ray photon which interacts with CCD detector can produce photoelectric effect and generate photoelectrons[1]. Under the ideal condition, the number of electrons is proportional to the energy of incident X-ray photon. Besides the electrons generated by X-ray absorbed in CCD is converted to readout voltage linearly. Therefore, the voltage is positively correlated with X-ray photon's energy, and we can measure X-ray energy spectra directly. But in reality, because of the charge cloud diffusion, surface charge loss and charge transfer loss in the detection process based on CCD, the spectral resolution (FWMH)is broadened. And in the mean time, the spectral peak becomes non-Gaussian with a shoulder and a flat shelf on the low energy side. In this paper, we develop the model and simulation of CCD's spectral redistribution, including photoelectric conversion process, charge collection process, charge transfer process, and charge readout process. Among other things, we mainly analyze the influence of charge transfer efficiency on X-ray energy spectra.