【作者】 何玲平；

【导师】 陈波；

【作者基本信息】 中国科学院研究生院（长春光学精密机械与物理研究所） ， 光学， 2010， 博士

【摘要】 地球等离子体层作为内磁层最重要的活跃区域之一,在揭示地球磁场的众多复杂的相互作用的过程中,是一个非常关键的研究对象。“嫦娥二期”工程中已经将基于光子计数探测器的月基极紫外(EUV)相机列为有效载荷,用于对地球等离子体层进行拍摄。极紫外光子计数探测器作为EUV相机的关键技术之一,其成像性能直接影响相机的研制水平。本论文对极紫外光子计数探测器的成像特性展开了深入研究,为工程研制提供了理论和试验依据。本文在楔条形阳极位置灵敏理论研究及仿真模型建立的基础上,验证了光子计数探测器成像应用的可行性。详细分析了倍增器件微通道板(MCP)的各项工作参数对探测器成像性能的影响,确定了其最佳工作状态;提出了位敏元件楔条形阳极的最优化设计原则,并给出了加工设计参数;介绍了探测器的前端电子系统,搭建数据采集系统,编写了图像采集及处理软件。提出检测方案,对探测器的图像分辨率、成像非线性、MTF、暗噪声、光子计数率等成像性能进行了检测,结果表明我们研制的楔条形光子计数探测器的分辨率达到了140um,光子计数率高达67k cps,图像整体非线性度低于0.3%;初步完成了对月基EUV相机进行整机的成像检测。针对月基EUV相机可能存在的离焦模糊和空间周期性噪声,我们提出用维纳滤波算法对图像进行离焦模糊的复原,通过频域陷波滤波器滤除周期性空间噪声,仿真实验表明上述算法能有效解决可能出现的图像问题。更多还原

【Abstract】 As one of the most important active regions in the inner magnetosphere, plasmasphere is a very critical factor to reveal many complex interactions in the Earth’s magnetic field. EUV Camera based on photon counting detector has officially become a payload in the "Chang’e 2" project, using to image Earth’s plasmasphere. As one of the key technologies of EUV camera, imaging performance of EUV photon counting detector impact on the developing level of the camera directly. This thesis carried out an in-depth research on the imaging characteristic of EUV photon counting detector, provided a theoretical and experimental basis for the project.Based on the theoretical study of wedge-strip anode, a simulation model of wedge-strip anode photon counting detector has been established and verifies the feasibility of its principles by the simulation target imaging. A Scheme design for the detector has been proposed, and Micro-Channel Plate’s various parameters have been optimized to ensure detector’performance; based on the the analysis of the main factors to position sensitive component (wedge-strip anode)’s imaging performance, an optimum design discipline of wedge -strip anode has been proposed and the design parameters has been given. Detector’s front-end electronic systems also have been introduced; a data acquisition system has been set up, and the image acquisition software has been coded. We introduced an imaging performance testing program for wedge-strip anode photon counting detector, which involved resolution test, linearity test, background noise test, and photon counting rate test. The testing result show that, our developing detector has a resolution of 140um, counting rate of 66k cps, linearity superior to 0.3%, fully able to meet the design requirements for EUV camera; has completed the imaging testing of the whole EUV carema preliminary. For the possible image problems of EUV camera, as defocus blur and spatial periodic noise, we propose Wienar filter algorithm to restore those defocus blurred images, and frequency-domain notch filter to filter out the cyclical spatial noise. Simulation result shows these methods can effectively solve the image problems that may arise.更多还原