X-ray Detector Integrated Technology Research

Because of its high photo energy and strong penetrating force, X-ray has been used widely in lots of areas. However, the existing X-ray detectors have some problem such as big bulk and inconvenience. To improve these deficiencies, an integrated X-ray detector has been designed in this issue, and several key technologies of this kind of detector have been analyzed and researched.The CsI(Tl) crystal is used as the light conversion material and the CCD is used as the photo receiver in integrated X-ray detector. A lay of CsI(Tl) film with the micro-column structure will be integrated on the surface of the CCD device. Al will be used to separate CsI(Tl) columns to inhibit the proliferation of fluorescence and improve the spatial resolution of the detector. The main works in this dissertation are as follows.Three mathematical model including continuous film model, crystal unit model and columnar crystal model have been made, which indicate the film with a micro-column structure has a higher fluorescence converting factor K than a normal film. K reaches its maximal value when the thickness of the film is 15μm or 70μm and reduces as the increase of the diameter of the micro-column.On the bases of the model, several CsI(Tl) films have been deposited by vacuum evaporation, and the optical metallographic microscope, square resistance testing and XRD have been used to investigate those films. The results indicate that: the deposition rate is higher or the substrate temperature is lower, the grain is smaller; it is much easier for CsI(Tl) film to form the crystal state on a crystal substrate; the crystal CsI(Tl) film has a preferred orientation in (200) crystal face; the crystalline quality of a 70μm-thickness film is good; if the thickness increases, cracks between the grains will appear and the density of the film will decrease.As the photo receiver CCD device will be damaged in a radiation condition, the mechanism of radiation damage has been analyzed by a neutron radiation model and an experiment ofγradiation on commercial CCD has been made in the last part of this dissertation. The results of both calculate and experiment show that the dark current of CCD will change linearly with the variation of radiation dose approximately.