新型变密度卤化物/MCP反射式X射线敏感薄膜的研究

Study on New MCP Reflection X-ray Sensitive Film of Variable Density Halide

在MCP输入端通道内壁制作了反射式X射线敏感膜层 ,提高了MCP对能量 35～ 5 0keVX射线的探测能力。实验结果表明 :变密度结构的CsI/MCP中膜层结构较密实时 ,其输出响应可提高 5～ 6倍 ,较无膜MCP提高 1～ 2个数量级 ,和CsBr、KBr相比较 ,以CsI的响应特性为最佳 ;膜层材料、结构、工艺和X射线能量等是影响探测能力的主要因素。

Microchannel plate (MCP) is a device of two dimension array electronic multiplier. The detection ability to 40～60keV X ray for MCP was increased by coating the halide such as CsI, CsBr and KBr on input plate of MCP, that forming a reflection X ray sensitive film in the channel with depth of 2～3 times of diameter below the input plate. Experiment results shown that the output response of MCP with variable density structure of CsI for X ray is about 5～6 times higher than that with constant density structure, and of one order of magnitude stronger than that without coating the film. Comparatively, the output response of MCP with CsI sensing film is best,but CsBr and KBr medium are not. The response characteristics of MCP with CsI for X ray related to film materials, structure, component distribution and fabrication process. Several experiment curves denoted the response characteristics to X ray at different target voltage and current. The results basically accorded with the theory about quantum detection efficiency of reflection X ray cathode. This new MCP reflection X ray sensitive film of variable density halide has been successfully applied on X ray imaging detecting devices. The corresponding detection system will find widely and potential applications in the field of medical diagnosis, nondestructive evaluation and security inspection etc.