V型耦合式刀片低能束流位置探测器及其性能检测

基于合肥国家同步辐射实验室(NSRL)低能量真空紫外光源的特点,研制了耦合式刀片低能束流位置探测器,用于在线监测波荡器辐射出的低能量真空紫外相干光源的稳定性.探测器采用V型耦合式刀片作为探针,基于错位安装、倾斜嵌入被测光束边缘和直流偏压捕集自由电子等技术有效增强光电效应,提高探针的响应灵敏度和探测器监测精度.介绍了耦合式刀片低能束流位置探测器的结构特点、探测原理和性能测试,在线监测了NSRL波荡器光源的稳定性,获得了一系列有价值的试验数据.结果表明:该探测器能完成NSRL-0.8GeV低能储存环上插入件光源的在线监测,满足对改造后的新光源各插入件辐射光束位置稳定监测的要求.     

NSRL二期工程新建的磁场测量系统

NSRL二期工程新建波荡器采用霍耳探头点测法,并使用"on fly"测量技术.为此专门研制了一台二维自动磁场测量系统,它包括测量行程3500mm机床和测量控制系统.通过对波荡器扫描点测量,得到了波荡器场形分布测量结果.     

光栅单色器及相关技术

国家同步辐射实验室（NSRL）通过建设国家大科学工程项目,在真空紫外和软X－光光学系统方面积累丰富的经验,建立了比较齐全的设计和检测等软件和硬件设施,本文介绍了NSRL已经研制及正在研制的光学单色器系统,以及在大型光栅光谱仪器技术方面的工作,包括光学设计、机械结构设计、超高真空技术,电子学硬件、软件设计和光学系统调试等内容。     

兼具高次谐波抑制的三镜偏振器

为了抑制同步辐射光通过光栅单色器后出射的单色光在长波段的高次谐波以及提高光源在该波段的偏振特性,计算分析了三镜偏振器Au_Si_Au的偏振特性及其对长波段高次谐波的抑制效果.比较了Au-Si_Au,Au_SiC_Au和Au_Be_Au 3种不同材料的偏振镜抑制高次谐波的能力和对偏振度的提高.计算分析表明,Au_Si_A...     

大曲率弧矢弯曲复合晶体的研制

为提升国家同步辐射实验室X射线吸收精细结构(NSRL-XAFS)的光束线性能,提出将现有双平面晶单色器改造成弧矢聚焦双晶单色器的思想。采取将晶体与钛合金复合的工艺,实现了晶体的大曲率弹性弯曲,并将其用作弧矢聚焦晶体单色器中第二晶体的成像元件。鉴于NSRL-XAFS实验的光学要求,设计制作了复合晶体试验模型,通过有限元分析计算和长程面形仪实际测量得到了不同弯曲半径下晶体的面形精度,并用激光模拟其聚焦性能。结果表明,在缩放比为1/3时,样品上的成像束斑水平尺度(FWHM)由43mm(无聚焦)缩小到3mm,光子密度提高了近一个量级。这些结果满足NSRL在现有光源条件下提升XAFS数据采集质量的要求。     

国家同步辐射实验室的LIGA技术研究及应用

LIGA技术是一种可以利用多种材料获得大高宽比微结构的微细加工方法。介绍了LIGA技术的原理和国家同步辐射实验室LIGA试验线站的参数。详细给出NSRL近年来在同步辐射光刻、微电铸和微塑铸等LIGA技术方面的研究进展,同时给出其在微惯性器件和微流体器件等LIGA应用方面的研究进展。分析LIGA技术研究及应用的发展现状以及所遇到的困难,结合同步辐射光刻的特点,提出LIGA应用的一些展望。     

基于多层膜的软X射线偏振测量

综述了过去10年中德国BESSY同步辐射装置在软X射线偏振测量方面所做的工作。在BESSY同步辐射装置中,有10条椭圆波动器光束线,这可使同步加速器辐射的偏振态从线偏振光(水平或者垂直)转变为左旋或右旋圆偏振光。由于很多偏振敏感实验(例如,MCD光谱测量)需要归一化量,因此对偏振度进行量化非常重要。对于偏振实验,即对光的偏振态测量来说,需要两个光学元件分别起相位片和检偏器作用。因此,专门研制了在软X射线区有透射和反射功能的多层膜,并对其做了优化。通过使多层膜参数(周期,厚度比)与构成材料的吸收边相匹配,即可获得共振加强的偏振灵敏度。由此可知,基于多层膜的偏振测量与这些偏振光学元件工作波长处性能测量密切相关,文中对仪器的设置和测试结果做了介绍,同时给出了磁性薄膜或光活化物质的磁光光谱测量和偏振测量的示例(法拉第和克尔效应)。     

软X射线偏振光学元件的设计与制备

叙述了软X射线波段反射式多层膜起偏器和检偏器的设计原则和设计方法,优化计算了5.9nm波长处多层膜光学元件的偏振性能,阐述了其制备的过程,利用小角度衍射法对多层膜的厚度进行了测量,并对同步辐射测量的反射率结果进行了拟合分析。     

符合飞行时间质谱技术与应用

介绍了合肥国家同步辐射实验室(NSRL)光化学实验站用于研究原子、分子结构及离子-分子反应的阈值光电子-光离子符合(TPEPICO)技术的实验装置。给出了用该技术获得的一些分子的符合飞行时间质谱(TOFMS)、阈值光电子-光离子符合谱(TPEPICOS)及光电离效率谱(PIES)。     

基于偏振干涉滤光片的宽波带偏振方向旋转器的设计

首次提出了基于偏振干涉滤光片设计方法的宽波带偏振方向旋转器。该旋转器实现了 380 nm～ 780 nm全波长范围内的偏振方向旋转。与普通的只针对某一特定波长的半波片相比 ,该偏振旋转器特性大大超越了普通 1 /2波片 ,并且入射角在± 2 0°范围仍实现偏振方向旋转 90°的要求。将该偏振方向旋转器用作 LCD或 LCOS投影仪中的偏振转换器 ,将大大提高系统的光能利用率以及投影系统的对比度。     

A simple method for formation of the matching input in a helical undulator

A helical undulator is widely used in free-electron lasers with pulsed electron beams. An adiabatic input with a length of 5–10 periods is commonly used to inject the beam. A novel and simpler method for matching the undulator input is proposed, theoretically investigated, and experimentally implemented. The end field is formed with the help of wire sections in the form of straight lines and circular arcs, which permits an accurate control of geometrical dimensions. The axial length of this section is ∼1/6 of the undulator period. Experimental results obtained on the undulator with a period of 4.8 cm agree well with theoretical data.     

Quick-scanning x-ray absorption spectroscopy system with a servo-motor-driven channel-cut monochromator with a temporal resolution of 10 ms

We have developed a quick-scanning x-ray absorption fine structure (QXAFS) system and installed it at the recently constructed synchrotron radiation beamline BL33XU at the SPring-8. Rapid acquisition of high-quality QXAFS data was realized by combining a servo-motor-driven Si channel-cut monochromator with a tapered undulator. Two tandemly aligned monochromators with channel-cut Si(111) and Si(220) crystals covered energy ranges of 4.0-28.2 keV and 6.6-46.0 keV, respectively. The system allows the users to adjust instantly the energy ranges of scans, the starting angles of oscillations, and the frequencies. The channel-cut crystals are cooled with liquid nitrogen to enable them to withstand the high heat load from the undulator radiation. Deformation of the reflecting planes is reduced by clamping each crystal with two cooling blocks. Performance tests at the Cu K-edge demonstrated sufficiently high data quality for x-ray absorption near-edge structure and extended x-ray absorption fine-structure analyses with temporal resolutions of up to 10 and 25 ms, respectively.     

Radiation of High-power Ultrawideband Pulses with Elliptical Polarization by a Conical Helical Antenna

A high-power source of ultrawideband radiation with elliptical polarization was developed on the basis of exciting a conical helical antenna by a bipolar voltage pulse with a length of 1 ns. The antenna parameters were preliminarily estimated using analytical formulas and then optimized via numerical simulation. The results of low-voltage test measurements were compared with the data that were obtained using a program that was developed on the basis of the finite-difference method in the time domain. In high-voltage measurements, the energy efficiency of the radiator was 0.85 and the coefficient of the hodograph ellipticity measured along the antenna axis was 0.9. The effective radiation potential of the source at an amplitude of bipolar voltage pulses of 190 kV was 270 kV, while the efficiency with respect to the peak field strength was 1.35. The high-power source of ultrawideband radiation operated at a pulse repetition frequency of 100 Hz.     

Calibration of a microchannel plate based extreme ultraviolet grazing incident spectrometer at the Advanced Light Source

We present the design and calibration of a microchannel plate based extreme ultraviolet spectrometer. Calibration was performed at the Advance Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL). This spectrometer will be used to record the single shot spectrum of radiation emitted by the tapered hybrid undulator (THUNDER) undulator installed at the LOASIS GeV-class laser-plasma-accelerator. The spectrometer uses an aberration-corrected concave grating with 1200 lines/mm covering 11-62 nm and a microchannel plate detector with a CsI coated photocathode for increased quantum efficiency in the extreme ultraviolet. A touch screen interface controls the grating angle, aperture size, and placement of the detector in vacuum, allowing for high-resolution measurements over the entire spectral range.     

High-precision soft x-ray polarimeter at Diamond Light Source

The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.     

Femtosecond synchronism of x-rays and visible/infrared light in an x-ray free-electron laser

A way is proposed to obtain ultrashort pulses of intense infrared/visible light in few-femtosecond synchronism with x-rays from an x-ray free-electron laser (XFEL). It makes use of the recently proposed emittance-slicing technique [Emma et al., Phys. Rev. Lett. 92, 074801 (2004)] to both restrict the duration of self-amplified spontaneous emission (SASE) to a few femtoseconds and to lead to a coherence enhancement of near-infrared transition undulator radiation (CTUR). The x-rays and the near-infrared light originate within the XFEL undulator from the same slice of electrons within a bunch and are therefore perfectly synchronized with each other. An example of realizing the scheme at the Linac Coherent Light Source is presented. A few side issues are explored briefly, such as the magnitude of the velocity term versus the acceleration term in the Lienard-Wiechert fields and the possible use of the CTUR as a diagnostic tool for the SASE process itself.     

基于双向反射分布函数的海面红外偏振特性表征模型

针对红外波段下海面偏振特性建模的问题,在双向反射分布函数的基础上,建立了海面微面元的偏振双向反射分布函数模型。综合考虑了海面的自发辐射效应和反射效应对探测器接收辐射的影响,提出了一种新的海面红外偏振特性表征模型。利用Elfouhaily海浪谱和快速傅里叶变换计算了海面的高度场信息和斜率信息。数值计算了不同观测天顶角和不同风速下海面自发辐射的线性偏振度,以及不同入射天顶角下海面反射辐射的线性偏振度,仿真生成了海面和舰船的红外偏振图像。仿真数据与文献数据的对比分析表明,本文所建立的红外偏振特性模型适用于分析海面的红外偏振特性。与传统的红外强度图像相比,红外偏振图像可以提供更多关于海面的细节信息。同时,目标与海面的偏振特征差异更明显,对比度更高。所提出的海面红外偏振特性表征模型对海上目标的探测识别应用具有重要的意义。     

Parametric modeling and contact analysis of helical gears with modifications

An approach for a mathematical model and contact analysis of helical gears including tip relief, root relief, end relief and longitudinal crowning modification was developed. First, tooth profile equations of non-modified involutes, tip reliefs, root reliefs and fillets were derived after applying gear principles and coordinate transformation to transverse cross section profiles of a rack cutter. Then the intersecting lines between different profiles were solved through by Gauss-Newton numerical method. Parametric modeling program of modified helical gears was obtained to automatically generate exact gear surfaces of tip reliefs, root reliefs, end reliefs and longitudinal crowning modifications via Matlab code. Subsequently, an example of helical gear pair in practical engineering was presented, and the solid model and finite element model with modification were established. Finally, the dynamic contact characteristic of helical gear pair was calculated by three-dimensional dynamic contact finite element method. It is expected that the proposed approach can be applied in analyzing the effect of modification on radiation noise prediction of gear system in further study.     

EUV Optical Design-Reflective and Diffractive Optics

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