SIMULATION OF THE X-RAY RESPONSE OF SCINTILLATOR COATED SILICON CCDS

Silicon CCD:s are used for X-ray imaging in fields as dentistry and ma terials testing. Due to the low X-ray absorption in silicon the CCD is generally coated with a scintillating layer. In order to evaluate the response for different combinations of scintillator material, scintil lator geometry and detector we have developed a simulation program. Th e program calculates the signal to noise ratio and spatial resolution based on both the signal from the scintillating layer and the signal f rom direct detection of Xrays in the detector. Results obtained with t his program indicate that the signal to noise ratio in the system is o ptimized by using a scintillator with high X-ray absorption and high l ight output while minimizing the signal from direct detection in the C CD. The spatial resolution can be increased by defining pixels in the scintillator.