方孔微通道板结构缺陷对成像质量的影响  

Influence of Structural Defect of Square-Hole Micro Channel Plate on Imaging Quality

作　　者：李旭[1,2] 何飞[1] 李达[1,2] 陈波[1] 

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院研究生院,北京100049

出　　处：《光学学报》2012年第10期84-93,共10页Acta Optica Sinica

基　　金：国家自然科学基金(10878004)资助课题

摘　　要：方孔微通道板(MCP)作为一种新型X射线波段光学成像系统,因其具有大视场、高分辨率、能够收集大量辐射并将其准直或聚焦等优点,越来越多地受到了人们的关注。但在MCP制作和加工过程中,难免会使微通道产生一定的结构缺陷,对其成像质量造成严重的影响。利用Tracepro软件建立了标准方孔MCP模型和具有不同结构缺陷的MCP模型,并基于蒙特卡罗(MTC)光线追迹方法对这些模型进行模拟成像。分别讨论了Taper型、Twist型和Nonsquare型结构缺陷对成像质量的影响。然后以溴钨灯作为光源,在可见光波段对实验室现有的4块方孔MCP进行了成像实验,所得实验结果与模拟结果基本吻合,验证了模拟结果的正确性。模拟和实验结果表明,以上3种结构缺陷均会造成十字像中央亮斑面积增大、强度降低等情况,所不同的是Taper型结构缺陷使会聚光线分裂成两条,而这两组平行的会聚线相交形成4个焦点,其能量要比单一聚焦能量衰减很多,从而对成像质量影响更大。该研究为今后研究曲面MCP和基于MCP的X射线光学系统奠定了重要基础。As a new X-ray imaging system, more and more plate （MCP） which has the properties of large field of view, attention has been paid to the square-hole micro channel high resolution, and collection of enormous radiation to be collimated or focused. However, during the fabrication and process of the MCP, it is hard to avoid generating structural defects in the square holes which greatly influent the imaging quality. The standard square-hole MCP model and MCP models with different structural defects are first set up with the software Tracepro, and then the simulative images of these models are simulated by ray trace method of Monte Carlo. Then the influences of structural defects of Taper type, Twist type and Nonsquare type on imaging quality are analyzed. Based on above simulations, the four samples of MCP are imaged in visible bands with a Nickel-Tungster source. The experimental results are consistent with the simulated images, proving that the simulations are correct. The experimental results show that, all of the three defects can result in area increase and intensity decrease of the central bright spot with expect that the third defect can divide the focused rays into two beams which forms four focus and makes the degradation of energy more serious and thus more seriously influence the imaging quality compared with the other two defects. This paper provides an important basis for the future researches on curved MCP and X-ray optical system based on MCP.

关 键 词：成像系统 X射线光学 微通道板 光线追迹 结构缺陷 

分 类 号：TH744[机械工程—光学工程] O434[机械工程—仪器科学与技术]