Properties of photon counting imaging system with Si thin films
采用Si薄膜的光子计数成像系统性能的研究

The Si thin films on ceramic substrates,which were fabricated by electron beam evaporation,were applied as charge induction layers in photon counting imaging system with induction readout. The structures and micrograph of Si thin films were studied. The X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM) images indicate that the thin film has amorphous structure and is coarse due to the lattice boundary of ceramic substrate. The experimental setup was established and the detector resolution,counting rate,pulse height distribution curves etc., with different Si film thickness were compared. The results suggest that the film thickness influences on spatial resolution less than on the counting rate. Moreover,the properties of the system with Si and Ge thin films of the same resistance were compared,which shows that the properties such as distortion,counting rate and dark count rate are better with the Si films.