变包含角平面光栅单色器光斑横移分析

介绍了变包含角平面光栅单色器的光路布局及结构组成,分析了影响单色器光斑横移的因素,对受力变形引起光斑横移的因素,运用有限元软件Ansys进行了数值模拟;根据模拟结果(0.33″)对单色器的相关部件加工精度进行误差分配;按照分配误差要求完成单色器结构设计、加工、组装,对单色器出射光斑横向角漂移重复精度进行了测试,结果为0.7″。     

变间距光栅刻线密度的测试精度分析

介绍了衍射法测量变间距光栅线的测量系统。该测量系统由激光器、淮直镜、光栅转动台（含角度测量仪）、直线工作台、光栅调节架、探测器和待测光栅组成。分析了系统中各种误差测量精度的影响,以及变间距光栅参数的变化对光学系统的影响和补偿方法。计算表明,该系统的测试精度满足光束线对光学系统的性能要求。     

可变包含角单色器的双轴平行度误差分析和测试

估算了可变包含角单色器的两个旋转轴之间的不平行度对波长的调整精度和分辨率的影响,以及采用平行光管测量两个旋转轴的不平行度大小和调整的方法。     

变间距光栅刻线密度测试系统的性能评价

在国家同步辐射实验室二期工程光束线的建设中,建立了一套变间距光栅刻线密度的测试系统。该系统采用衍射测量法测量光栅间距的变化,可以对光栅长度为100 mm的平面和凹面光栅的刻线密度进行测量。样品测量结果表明,该系统的测量精度△N/N<2×10~(-4),满足光束线工程的要求,可以作为NSRL进口的变间距光栅的验收工具。     

光栅单色器中精密直线位移的测试与标定系统

在同步辐射光束线建设中,为达到单色器的光谱分辨率要求,对波长扫描机构的定位精度要求在μm量级.我们建立的由激光干涉仪、自准直仪组成的直线位移测试系统,可以对直线位移机构进行测试并对机构的直线位移编码器进行标定.该系统不但实现了直线位移的精密测量,还能对机构的直线性进行测量.应用该系统测出位移范围为160 mm的直线位移机构的重复精度为1.0×10-3mm,分辨率达75×105mm,对光栅尺的标定精度达到RMS=3.0×10-4mm.     

Implementation of effective control system for variable-included angle plane-grating monochromator

The variable-included angle plane-grating monochromator is a homemade key equipment of the scanning transmission X-ray microscopy (STXM) beamline at Shanghai Synchrotron Radiation Facility (SSRF).Monochromatic light of various wavelengths is achieved by an effective control system that handles the rotation of the plane mirror and plane grating mounted in a high vacuum chamber.M511.DDB made by PI Corp.is used as motion stage which has a DC servo motor controlled by a C862 controller based on RS232 protocol.The software platform of STXM is EPICS,so the local control functions are implemented by LabVIEW program to satisfy physics control.For the remote control functions,the program is integrated into EPICS with ShareMemoryIOC.Experimental tests show that the repeat precision of motion control is less than 0.2μm,which meets the control demand.     

Cooling of double crystal monochromator with sagittal focus at SSRF

In SSRF, the design of 1st crystal cooling geometry of double crystal monochromator with sagittal focus is mainly reported by China. Our simulation indicates that the broadening of the full width at half maximum of the rocking curve of the double crystal monochromator induced by the heat load is about 3.7 μrad, and is in agreement with the experimental value of 5 μrad. Our scheme showed that the photon flux is reliably linear with electron current of the storage ring, which is extracted from the monochromator.     

BSRF-1W2A光束线弯晶单色器的改进

为解决北京同步辐射装置(BSRF)小角散射实验站样品处光斑的水平聚焦效果差、光斑展宽及光斑水平位置随流强变化有一定的移动等问题,本文设计了一种能够满足实验站稳定用光的新的弯晶单色器.     

低速高电荷态离子Xeq+在金属Al(111)面掠角散射的中性化过程研究

本文在经典过垒模型(COBM)下,通过计算机模拟研究了低速高电荷态离子Xeq 在金属Al(111)表面掠角散射过程中,高电荷态Xeq 离子的中性化过程、其电荷态与该高电荷态离子到Al(111)表面的距离R的关系.此外,还计算了不同电荷态的Xeq 离子在掠射过程中所获得的镜像能,并把该结果与实验值进行了比较.我们模拟的镜像能与实验值符合得非常好.     

Extraction of Am(III) at the Interface of Organic-Aqueous Two-Layer Flow in a Microchannel

Extraction of Am(III) was performed at the interface of organic-aqueous two-layer flow in a micro-channel having an asymmetric cross section. A solution of 3 mol/dm³ nitric acid containing ²⁴³Am(III) and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphineoxide diluted with n-dodecane were introduced into the microchannel as the aqueous phase and organic phase, respectively. The two phases formed a stable two-layer flow with an interface parallel to the sidewall of the microchannel, and they were separated from each other at the divergence point of the microchannel. The extraction reaction of Am(III) proceeded at the interface of the two phases, and reached the equilibrium state while the two phases passed through the microchannel.     

西安脉冲堆3He快中子夹心谱仪的方案设计

本文介绍了3He快中子夹心谱仪的气体填充、探测器、三通道数字符合和数据分析处理系统,描述了探测器系统的理论分析及实验标定方法,提出了谱仪符合本底计数的来源,绐出了扣除几种符合本底的理论和实验方法,研究结果表明本工作可指导3He快中子夹心谱仪的深入研究.     

Computer simulation of sputtering at the low index (1 0 0), (1 1 0) and (1 1 1) surfaces of Ni3Al in a STEM

The present study is relevant to the preferential Al sputtering and/or enhancement of the Ni/Al ratio in Ni₃Al observed by the scanning transmission electron microscopy fitted with a field emission gun (FEG STEM). Atomic recoil events at the low index (1 0 0), (1 1 0) and (1 1 1) surfaces of Ni₃Al through elastic collisions between electrons and atoms are simulated using molecular dynamics (MD) methods. The threshold energy for sputtering, E_sp, and adatom creation, E_ad, are determined as a function of recoil direction. Based on the MD determined E_sp, the sputtering cross-sections for Ni and Al atoms in these surfaces are calculated with the previous proposed model. It is found that the sputtering cross-section for Al atoms is about 7-8 times higher than that for Ni, indicating the preferential sputtering of Al in Ni₃Al, in good agreement with experiments. It is also found that the sputtering cross-sections for Ni atoms are almost the same in these three surfaces, suggesting that they are independent of surface orientation. Thus, the sputtering process is almost independent of the surface orientation in Ni₃Al, as it is controlled by the sputtering of Ni atoms with a lower sputtering rate.     

Development of the high-energy neutron fluence rate standard field in Japan with a peak energy of 45 MeV using the 7Li(p,n)7Be reaction at TIARA

In this study, we developed a 45 MeV neutron fluence rate standard of Japan. Quasi-monoenergetic neutrons with a peak energy of 45 MeV in the neutron standard field were produced by the ⁷Li(p,n)⁷Be reaction using a 50-MeV proton beam from an azimuthally varying field (AVF) cyclotron of the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA). The neutron energy spectrum was measured using an organic liquid scintillation detector and a ⁶Li-glass scintillation detector by the time-of-flight method, and using a Bonner sphere spectrometer by the unfolding method. The absolute neutron fluence was determined using a proton recoil telescope (PRT) composed of the liquid scintillation detector and a Si(Li) detector that was newly developed in the present study. The detection efficiency of the PRT was obtained using the MCNPX code. The peak neutron production cross section for the ⁷Li(p,n)⁷Be reaction was also derived from the neutron fluence in order to confirm the neutron fluence of the TIARA high-energy neutron field. The peak neutron production cross section obtained in the present study was in good agreement with those of previous studies. The characteristics of the 45-MeV neutron field in TIARA were successfully evaluated in order to calibrate high-energy neutron detectors and high-energy neutron dosimeters.