棱镜摄谱仪的数字化成像与光谱分析

讨论现有棱镜摄谱仪成像方法的不足,介绍一种用数码照相CCD成像技术改造棱镜摄谱仪和计算机程序处理进行光谱分析的方法;本设计的棱镜摄谱装置能够清晰地拍摄标准光谱与待测光谱.可以通过数码照相机二合一功能或者计算机程序处理将两者成像在一张图片一上.它既可以从各条彩色谱线的颜色上用目测分辨出其大致波长值,又方便于两者之间的比较与精确测量;用该技术改造后的棱镜摄潜仪成像比较直观,清晰度高,花费低廉,结构简单、紧凑,在工矿企业和高校物理实验中有较好的实用价值.     

Wide band focusing x-ray spectrograph with spatial resolution

A new, wide spectral bandwidth x-ray spectrograph, the wide-bandwidth focusing spectrograph with spatial resolution (WB-FSSR), based on spherically bent mica crystals, is described. The wide bandwidth is achieved by combining three crystals to form a large aperture dispersive element. Since the WB-FSSR covers a wide spectral band, it is very convenient for application as a routine diagnostic tool in experiments in which the desired spectral coverage is different from one test to the next. The WB-FSSR has been tested in imploding wire-array experiments on a 1 MA pulsed power machine, and x-ray spectra were recorded in the 1-20 A spectral band using different orders of mica crystal reflection. Using a two mirror-symmetrically placed WB-FSSR configuration, it was also possible to distinguish between a real spectral shift and a shift of recorded spectral lines caused by the spatial distribution of the radiating plasma. A spectral resolution of about 2000 was demonstrated and a spatial resolution of approximately 100 microm was achieved in the spectral band of 5-10 A in second order of mica reflection. A simple method of numerical analysis of spectrograph capability is proposed.     

Characterization of a polarization-resolved high spectral resolution UV-visible spectrometer

To measure the degree of polarization of a plasma emission, a polarization-resolved UV-visible Czerny-Turner-type spectrometer was designed and constructed. For a high spectral resolution, F=1 m mirrors were used as a focusing and collimating mirrors and the incidence angles to the mirrors were determined to eliminate coma. The effect of astigmatism was reduced by designing the incidence angles to the mirrors to be as small as possible. The flat focal plane condition proposed by Reader [J. Opt. Soc. Am. 59, 1189 (1969)] was used to determine the grating position. The measured spatial resolution was 170 microm. To simultaneously measure the intensities with two perpendicular polarizations, a calcite crystal was placed after the entrance slit of the spectrometer. The change in the imaging property of the spectrometer due to the calcite crystal was measured and minimized. The spectral resolution was experimentally measured with a laser produced plasma to be 0.05 nm at 348 nm. The resolving power measured is 6600.     

On certain features of spectrum recording and photometric measurements of spectral lines using a MFS-MAES-based digital spectrograph

Features of recording spectra and performing photometric measurements of spectral lines using a digital spectrograph, which is based on an MFS-8 setup with a MAES multichannel emission spectrum analyzer (photodiode array assembly), are studied. Possibilities of optimizing the analytical signal and time parameters of the spectrum exposure for extending the linear range of the calibration curve and increasing the concentration sensitivities both in areas of low and high contents of determined elements by the atomicemission spectral analysis are shown.     

基于有限元法的高分辨透射光栅谱仪关键件结构优化设计

光栅室作为高分辨透射光栅谱仪的关键件,对谱仪整体稳定性起决定性作用.文中运用Pro/E对光栅室进行三维建模,以结构质量最轻为优化目标,截面尺寸为设计变量,建立优化模型,求得最优截面参数.运用ANSYS进行动静态分析,分析结果表明,优化后的光栅室刚度、强度均满足设计要求,结构前4阶固有频率均大于耙球基频40 Hz,不会发生共振.     

看谱镜在生产过程中的应用

介绍看谱镜的工作原理,分析前准备工作及实例检测。     

EUV波段CCD相机及其空间分辨率测试

研究了EUV波段CCD相机及其空间分辨率测试.EUV波段相机由荧光屏、MCP像管、光锥和可见光CCD构成,CCD像元大小为14 μm,像元数2 048×2 048.在北京同步辐射装置光束线软X射线光学实验束线站3W1B上,利用透射网栅法对相机进行了空间分辨率测试,结果显示这种结构的CCD相机在17.1 nm波长处,空间分辨率达到19 μm,相当于极限分辨率为26 lp/mm.     

High spectral resolution, real-time, Raman spectroscopy in shock compression experiments

The use of Raman measurements to examine molecular changes associated with shock-induced structural and chemical changes in condensed materials often poses two challenging requirements: high spectral resolution and significantly reduced background light. Here, we describe an experimental method that addresses these requirements and provides better quality data than the time resolved approach used previously. Representative measurements are presented for shock compression of two energetic crystals: pentaerythritol tetranitrate and cyclotrimethylene trinitramine. The high spectral resolution data have provided insight into molecular changes that could not be obtained from lower-resolution, time-resolved methods.     

基于谱聚类的高分辨率全色遥感影像分割

为了协调高分辨率全色遥感影像区域和边界的最优分割,提出了一种基于像素邻域和光谱特征的谱聚类高分辨率全色遥感影像分割方法。该算法重点着手于构建影像图模型,在其中引入像素邻域作用并充分顾及像素光谱测度差异。假定邻域像素具有连接关系,并在此基础上构建影像连接矩阵,再考虑像素光谱测度差异的影响建模像素间相似性,最终结合像素连接性和相似度构建影像权值矩阵完成图模型建立;而后在图模型的基础上,采用对权值矩阵特征分解并就分解结果进行选择的方式将影像数据变至低维特征空间,进而对获取的新数据执行FCM聚类算法达到影像分割目的。为了验证提出算法的有效性,分别对模拟影像和高分辨率全色遥感影像进行分割实验,定性、定量的评价结果表明了该算法的可行性与优越性。     

On the role of spectral resolution in velocity shear layer measurements by Doppler reflectometry

The signal quality of a Doppler reflectometer depends strongly on its spectral resolution, which is influenced by the microwave beam properties and the radius of curvature of the cutoff layer in the plasma. If measured close to a strong perpendicular velocity shear layer, the spectrum of the backscattered signal is influenced by different velocities. This can give rise to two Doppler shifted peaks in the spectrum as observed in TJ-II H-mode plasmas. It is shown by two-dimensional full wave simulations that the two peaks are separable provided the spectral resolution of the system is sufficient. However, if the spectral resolution is poor, the two peaks blend into one and yield an intermediate and incorrect velocity.     

Fizeau interferometer system for fast high resolution studies of spectral line shapes

A monochromator∕Fizeau interferometer∕intensified CCD camera system is described that was developed for the measurement of the shape of spectral lines that are rapidly time varying. The most important operating parameter that determines the performance of the instrument is the size of the entrance aperture as this determines both the light throughput and the effective interferometer wavelength resolution. This paper discusses, both theoretically and experimentally, the effect of the finite source area on the instrumental resolution to assist in optimizing the choice of this parameter. A second effect that often produces a practical limit to the quality of the spectra is drift of the interferometer plates. Measurements of the shapes of spectral lines of ions and atoms ejected from the cathode spot of continuous and pulsed cathodic arcs are presented to demonstrate the utility of this instrument.     

椭圆弯晶谱仪分析器研制

针对激光惯性约束核聚变辐射的X射线分析,可得到关于等离子体电子密度、温度、电荷分布等重要信息.研究的X射线弯晶谱仪分析器是用来诊断X射线光谱,进而实现对激光惯性约束核聚变的控制.探讨了椭圆弯晶谱仪理论原理,分析了积分反射率和质量吸收系数.弯晶谱仪采用LiF弯晶分析器,椭圆焦距2c为1 350 mm,椭圆离心率e为0.958 6,晶体布拉格角范围为30°至60°.在此对LiF弯晶分析器的制作工艺进行详细描述.实验结果表明,该晶体分析器对X射线的分辨率(λ/Δλ)可达900以上,能够用来对激光等离子体的X射线光谱进行诊断.     

Design of echelle spectrograph CCD camera

为了高精度采集中阶梯光栅光谱仪的谱图,设计了一种适用于中阶梯光栅光谱仪原理样机的高性能面阵CCD相机.首先,根据中阶梯光栅光谱仪的谱图特点和CCD芯片的特性,设计了面阵CCD相机的时序产生电路、驱动电路及数据采集处理电路,实现了面阵CCD相机的低噪声、高灵敏度以及高动态范围.然后,利用LabVIEW编写了CCD相机测试软件.最后,利用设计的面阵CCD相机对汞灯谱线进行了测试.结果表明:面阵CCD相机获取的二维谱图图像清晰、信噪比较高;经二维谱图还原后,可以得到标准的汞灯谱线.该相机性能稳定、可靠,满足中阶梯光栅光谱仪原理样机的研制要求.     

The spectral signal-to-noise ratio resolution criterion: computational efficiency and statistical precision

This note describes a practical improvement in the computational efficiency of the spectral signal-to-noise ratio (SSNR) resolution criterion for correlation-averaged images. The total set of N images is randomly partitioned into ng subsets, each subset is separately averaged, and a reduced form of the SSNR is computed from these average images. In general, larger values of ng achieve lower statistical uncertainty, while smaller values of ng are computationally more expedient. It is shown that, for negatively stained data, a judicious compromise is achieved with 10 less than or equal to ng less than or equal to 20, regardless of how large N may be.     

双通道椭圆弯晶谱仪的光学设计

根据椭圆几何光学和X射线晶体的布拉格衍射原理,进行了弯晶谱仪的光学设计.设计的椭圆离心率和焦距分别是0.958 6 mm和1 350 mm,椭圆的弧长是125.64 mm,光路的光程为1 443.30 mm;布拉格衍射角为30～67.5°,谱线探测角为55.4～134°;柱面镜的掠入射角为3.7°,半径为10 127 mm;谱线探测器的阴极面中心到狭缝的距离是35 mm.利用LiF、PET、MiCa和KAP晶体作色散元件,测量的波长范围是0.20～2.46 nm,晶体的尺寸是125 mm×8 mm×0.2mm.此外,将两个弯晶进行上下对称交叉和前后错开布置,减小了谱仪的尺寸和减轻了它的重量.     

A spectral system with the spatial resolution for plasma motion detection in the GOL-3 multi-mirror trap

A spectral system with the spatial resolution intended for diagnosing rotation of the plasma in the GOL-3 facility is described. The system is capable of measuring the radial dependences of the Doppler shift and broadening of spectral lines emitted by the plasma from various points in it. A DFS-24 double focusing spectrometer with a reciprocal linear dispersion of 0.45 nm/mm is the basis for the spectral system. If a radiation source is axially symmetric and extended, it is possible to obtain the intensity of spectral lines on the surface of the photosensitive area of a CCD array with the spatial resolution across the plasma by forming an image of the plasma in the sagittal focal plane of the entrance collimation lens, though the spectrometer astigmatism is strong. As a result, a spatial resolution of 0.8 mm has been attained in the developed system at a 55-mm field of view.     

车工平行度研究

分析了车工平行度超差的主要原因以及超差后造成的主要影响,介绍了车工平行度在产品质量中的重要性.通过具体案例介绍了中国重汽大同齿轮公司主要的控制及检验盘齿类工件车工平行度的方法.     

High resolution at low beam energy in the SEM: resolution measurement of a monochromated SEM

The resolution of secondary electron low beam energy imaging of a scanning electron microscope equipped with a monochromator is quantitatively measured using the contrast transfer function (CTF) method. High-resolution images, with sub-nm resolutions, were produced using low beam energies. The use of a monochromator is shown to quantitatively improve the resolution of the SEM at low beam energies by limiting the chromatic aberration contribution to the electron probe size as demonstrated with calculations and images of suitable samples. Secondary electron image resolution at low beam energies is ultimately limited by noise in the images as shown by the CTFs.     

干涉仪和棱镜摄谱仪的常见故障及修理方法

为了延长光学仪器的使用寿命,保证学生光学实验的正常进行,必须对实验室现有的光学仪器进行科学保养和维修。迈克尔逊干涉仪和小型棱镜谱仪是两种精密的物理光学仪器。试图对这两种仪器的工作原理和常见故障现象,产生故障的原因及排除方法进行仔细深入的分析、探讨。文中修理方法是笔者多年修理经验的总结。     

Results of high resolution slip measurements in a fretting experiment

An optical method of slip measurement in a fretting experiment has been developed which allows the measurement of slip amplitude to ±0.95 μm. Average sliding velocities of fretting interfaces during each 1.9 μm of relative motion can be calculated from the slip measurement data. Results on 4130 steel indicate that previously reported temperature variations of the fretting interface closely follow the pattern of the instantaneous sliding velocity of the interface, as is expected for frictional heating. The pattern of sliding velocity versus time is very regular from one fretting cycle to the next. It is concluded that any welding or adhesion which occurs at the interface is either on such a small scale that it does not disrupt the regular motion of sliding parts or is so infrequent in occurrence that it was not observed in any of the present experiments.