We designed hybrid x-ray detector and simulated using Monte Carlo method. Hybrid x-ray detectors consist of scintillator coupled photoconductor structure. In the hybrid structure, x-ray photons are converted into the light photon in the scintillator layer and light photons are converted into the electric charge in the semiconductor layer. The electric charges can be generated from directly x-ray absorption in the semiconductor material. We design the columnar CsI:Na as scintillator layer and a-Se as photoconductor material. When x-ray photon incident the scintillator layer, the photons are distributed through the scintillator, and then generated light photon influence the semiconductor material. We study the light photon distribution according to the scintillator layer thickness and the detector pixel size which have influence on image resolution.
We have designed a detector based on a-Se(amorphous Selenium) and done simulation the detector with Monte Carlo method. We will apply the cascaded linear system theory to determine the MTF for whole detector system. For direct comparison with experiment, we have simulated 139um pixel pitch and used simulated X-ray tube spectrum.