Image noise properties of a phosphor-coated CCD X-ray detector

We are investigating on the imaging characteristics of a CCD X-ray detector based on the direct deposition of a scintillator onto the CCD surface. The overall performance of the system depends on the relative weight of two types of interaction: the scintillation photons interaction and the direct interaction of the X-rays within the CCD. Two different thicknesses of a Gd2O2S : Eu screen have been chosen as scintillator coating, 100 and 200 μm, respectively. Image noise has been measured for three different beam qualities and its dependence on the input beam X-ray energy is discussed