THGEM探测器X光斑寻迹和位置分辨实验研究

介绍了一种基于THGEM的X射线光斑寻迹探测器,用于X射线单光子计量技术研究和测量,探测器有效面积200 mm×200 mm,采用128路基于ASIC和FPGA的高速读出电子学,探测器分为中间高分辨区和外围低分辨区两部分,两部分共用一套读出电子学。实验在中国计量科学研究院利用X光机产生的束线,测试光斑位置、光斑精细分布以及探测器的位置分辨。实验结果表明,探测器实现了同时对光斑寻迹和光斑的精细测量,探测器中间高分辨区x方向的位置分辨率为0.63 mm（FWHM）,y方向位置分辨率为0.62mm（FWHM）,探测器各项性能指标均达到了预期目标。This paper introduces the detector of X-ray spot tracing based on the THGEM. It is used for X ray single photon measurement technology research and measurement with an effective area of 200 mm×200 mm. The circuit board has 128 array of high speed readout electronics based on ASIC and FPGA. And it is divided into two parts:the middle area of high sensitive and the peripheral area of low sensitive. The two parts share a set of readout electronics. The experiment tests the position and the fine structure of the beam line produced by X ray machine in National Institute of Metrology. The results of the experimental show that the detector realizes both the spot tracing and the fine structure of the spot. The position resolution is 0.63 mm in x direction and 0.62 mm in y direction in high sensitive of the detector, which achieve the desired goal of preliminary design.     

机械刻划光栅的光线追迹方法

为了评价光栅的光谱质量,完成所设计光栅的光线追迹,针对机械刻划光栅的光线追迹提出了一种改进方法.在费马原理的基础上利用光程函数法得到入射光通过光栅后的光谱分布情况,再使用传输矩阵的计算方法构造出光谱的点列图.该方法适用于刻划在平面、球面和非球面基坯上的等间距和变间距光栅,光栅的光谱面可以为平面或者二次曲面. 通过刻划在非球面基坯上的凹面光栅验证了光线追迹方法的可靠性.     

一维粗糙面散射的射线追踪法研究

在考虑遮蔽效应的情况下,应用射线追踪法对一维导体和介质的高斯粗糙面的散射系数进行了研究,并分别计算了考虑一次反射和二次反射的散射系数。同时,利用蒙特卡罗法生成一维高斯粗糙面,计算了考虑一次、二次反射和遮蔽时不同均方根斜率粗糙面的平均散射系数。     

Specially profiled reflector for spherical front beams focusing

Focusing the power emitted from a source with spherical wave front by a specially profiled reflecting surface has been attempted using the simple ray tracing method. The reflector (mirror) surface profile that achieves such power redistribution is obtained from solving an ordinary first order differential equation using common numerical techniques. Furthermore, the proposed methodology can be useful to design complex reflectors for the electomagnatic and the acoustic systems, which finds broad engineering, industrial and biomedical applications.     

Normal tracing deflectometry using a secondary light source

Scanning deflectometric profilers based on an f–gθ system are typical optical tools used to measure mirror profiles at many synchrotron facilities. Unlike these profilers, which are based on a pencil beam, here a secondary light source and a pinhole are used to construct a system that automatically selects a beam that will always pass through the pinhole and propagate along the normal direction of the measured area on the surface under test. By measuring the angle variation of the selected beam, slope variations of the surface under test can be measured. Systematic errors introduced by manufacturing defects or aberrations of an optical element, which greatly degrade the performance of traditional profilers, could be minimized by using the developed method. Simulation values of the proposed method and a conventional method are compared.     

全息干涉条纹图的计算机自动处理与识别

本文应用数字图象处理与识别技术在IBM-PC/AT微处理计算机图象处理系统上对复杂的全息干涉条纹图进行了自动分析,文中采用二维灰度值检测的方法获取条纹的准峰或谷值二值图形,然后通过细化得到条纹中心,提出了用记忆跟踪算法自动去除毛刺和噪声线段.在用光标进行人机对话标定零级条纹后,可自动识别出其它整数条纹级数.分数级条纹级数可在整数级条纹数据之间进行线性或非线性插值得到.最后给出了全息条纹图分析的实例.     

具有渐近平均跟踪性质的系统

简记渐近平均跟踪性质为AASP.对于紧致度量空间上的连续映射f,证明了:(1)f有AASP当且仅当其逆极限空间上的移位映射有AASP;(2)若f有AASP且是等度连续的,则f是极小同胚.此外,讨论了AASP的拓扑共轭不变性.     

由边界退化确定模糊尺寸

在高能闪光照相流体动力学实验中,模糊问题严重影响诊断结果的精度。模糊图像的边界检测结果与真实边界之间往往存在位置偏移,称为边界退化量。在照相布局和客体确定的条件下,模糊尺寸越大,边界退化量越大。利用边界退化量与模糊尺寸的这一关系,提出一种从边界检测中测量系统模糊尺寸的新想法,从闪光照相成像物理过程角度阐释了方法的原理,然后通过数值实验分析了方法的处理过程,建议测量实验利用倒锥准直器对球形客体成像。模拟结果表明：采用该方法模糊函数的FWHM误差小于1个像素。最后借助数值模拟对台阶客体照相实现了对模糊尺寸测量结果的验证。     

片状放大器泵浦腔屋脊形反射器性能分析

用蒙特卡洛光线追迹法模拟和比较屋脊形截面反射器与平板反射器的光传输性能 ,分析反射器构型对泵浦腔性能的影响。三维光线追迹结果显示：在本文设定的腔体构型条件下, 屋脊形反射器腔的光传输效率可达63％,优于平板反射器腔的传输效率(η≤56%)。     

制冷型红外光学系统温栏杂散辐射分析及消除方法

在致冷型红外光学系统中加入温栏会引入杂散辐射。杂散辐射包括温栏自身的辐射及对外部热光的反射。这两种辐射进入探测器后,会降低系统的信噪比和动态范围,影响成像质量。基于辐射及传热理论,提出温栏杂散辐射所引起噪声等效温差的计算模型,并研究了消除温栏杂散辐射的方法。用LIGHT TOOLS进行了光线追迹,对比分析了传统平面环状温栏和球面反射镜型温栏的杂散辐射,验证了理论推导的正确性和消除方法的可行性。结果表明,采用半径为30.3 mm的高反射率球型温栏代替原设计中的粗糙平面型温栏,控制其曲率半径和位置,可使由温栏引入的杂散辐射降低99%以上。