软X射线光发射电子显微镜光束线聚焦用KB镜系统

研制了光发射电子显微镜(PEEM)高精度微聚焦系统,以实现上海光源软X射线PEEM光束线的高质量聚焦。根据上海光源PEEM光束线的概况,给出微聚焦系统光学元件的基本参数。基于Kirkpatrick-Baez(KB镜)两镜方案,设计了PEEM线微聚焦系统。介绍了KB镜姿态调整机构的设计方案,即利用三垂直线性驱动装置和两水平线性驱动装置相结合来实现五维调节,分析了姿态调节机构的原理与工作过程,给出了微聚焦系统的整体设计方案。测试了KB镜系统的机械性能,给出水平调节机构以及第一面镜子Pitch运动的测试结果,结果显示:水平调节机构分辨率为0.6μm,重复精度为0.85μm,Pitch角度分辨率为0.4″,重复精度为0.5″,优于指标要求。其它参数的测试结果亦均优于指标要求。实验表明,微聚焦系统机械指标的实现保证了PEEM线光斑的高质量聚焦。     

谱学显微光束线光斑水平漂移分析与检测

为提高上海光源搭建的国内首条软X射线谱学显微光束线站的整体性能,分析了其分光装置一变包含角平面光栅单色仪在波长扫描过程中影响谱学显微光束线光斑水平漂移的各个因素,推导出了各因素与光斑水平漂移的传递关系,并结合具体要求进行了误差分配.针对光斑水平角漂移重复精度的检测,采用自准直原理,构建了测试系统.利用该系统,完成了谱学显微光束线站光斑水平漂移重复精度的离线检测,其结果为0.67″,满足设计指标1″的要求.对安装调试后的束线进行了总体性能测试,结果均满足谱学显微设计和使用要求.由此表明,提出的对谱学显微光束线光斑水平漂移误差来源的分析及检测方法,有效保证了束线性能的实现.     

螺旋型波荡器辐射特性及光束线前置镜热载分布

对合肥国家同步辐射实验室(NSRL)引进、装备的螺旋型电磁波荡器进行了改造和性能研究,该螺旋型电磁波荡器被插入电子储存环的直线段,来产生高通量圆偏振相干光,提供一条真空紫外光束线,用于燃烧科学研究.基于NSRL改造后的光源参数,分析其同步辐射偏振特性,计算了该波荡器辐射出的总功率和功率密度分布,以及受其直接辐照的光束线...     

微量样品的AMS^14C年代测量

微量样品的AMS14C年代测量具有十分重要的意义,特别是对于一些珍贵的考古样品或含碳量极少的地质样品尤其如此。近两年来,北京大学AMS研究小组对系统和测量方法进行了一系列的研究和改进工作。包括改进制样流程、提高离子源样品利用率、优化整个束线的传输和改进数据获取与处理系统。已成功地测量了一系列小于100μg的微量样品。     

硬X射线磁圆二色谱预研获成功

3月14日，北京同步辐射装置1W1A束线XAFS实验站成功获得：Pt L吸收边的硬X射线磁圆二色谱(XMCD)”。XMCD是探测样品对X射线左旋和右旋偏振光吸收由磁场引起的差异，直接给出轨道和自旋角动量分布和作用的信息，是开展磁性材料电子和磁结构研究的重要手段。     

“癌细胞爆破性治疗”的亚分子微观信息程序过程10~8eVP~+/C~(n+)在DNA中H键、共价键、离子键的不同LET

2014质子P~+/碳离子C~(n+)束线治癌中心在上海建成后,媒体出现一个新名词:"癌细胞的爆破性治疗",突显了P~+/C~(n+)比传统的X、γ光子治癌更有效。还发展了XCT-NMRCT-PET精准控制P~+/C~(n+)束线在癌变区"爆破"。本文对"爆破癌细胞"的BBBB微观公式及其中的宏观量平均电离能I作微观分析,定量说明C~(n+)比P~+更有效,并说明有比"爆破"更深入的阻抑癌变DNA无序分裂信息键的先后程序。     

同步辐射装置的高输出环面光栅单色器和VUV光束线

本文讨论了由柱面反射镜和直槽环面光栅组成的掠入射单色器。柱面反射镜用来形成一个无象散彗差的单色器系统。这个单色器有很大的水平接收角。计算结果表明谱线增宽主要来自环面光栅的离焦。可以得到预期的单色器性能。本文也详细描述了单色器光学设计程序和同步辐射VUV光束线方案。     

多种材料软X光平面镜反射率标定

利用北京同步辐射装置(BSRF) 3W1B束线及反射率计靶室,在束流强度40～120mA、贮存环电子能量2GeV专用光运行模式下,做了不同材料掠入射平面镜反射率标定实验。标定过程用高灵敏度无死层的硅光二极管代替X射线二极管(XRD)作探测器,使输出信号提高2～3个量级,可标定能区从150～270eV拓展为50～1500eV能区,对C,Si和Ni材料平面镜给出完整的反射率标定曲线,最终把实验数据与理论计算比对并分析。     

超高真空精密四刀狭缝的结构原理及有限元分析

针对上海光源X射线干涉光刻(XIL)光束线对狭缝精度的要求,提出了一种应用于超高真空的精密四刀狭缝机构及热缓释方案.给出了四刀狭缝机构的工作原理,其四个缝片独立运动,采用线性驱动装置及精密直线导轨来实现开合.根据XIL光束线的特点,设计了一种合理有效的热缓释方案,对缝片进行了热-结构耦合分析.对狭缝的精度指标进行了测试.结果显示:该四刀狭缝的分辨率优于0.1μm、运动重复精度优于2μm、刀口直线度优于2.5 μm、平行度优于0.5 mrad,可以精确实现狭缝在水平和垂直方向-5～250 μm的开度,缝片在热负载下的最大热变形控制在0.034μm.得到的结果表明,该精密四刀狭缝具有高的精度和稳定性,可满足XIL光束线的使用要求,现已实际使用并制备出了100 nm周期的刻蚀线结构.     

起动故障分析及进口起动机的维修方法实例

从系统工程学的观点看,起动系是工程机械整机大系统中的一个子系统。理论和实践表明,起动故障不全是由起动系的故障引起的,还与工程机械大系统中的其他子系统(柴油机、操纵系统……等)、环境因素(气温、气压、湿度……等)有关。 一、从系统工程学观点探索起动故障的原因 1.不能起动或起动困难 (1)主机变速操纵杆未放在空档位置,发动机带有负荷。 (2)主机性能差 喷油泵不供油、喷油定时不对、雾化不良 高压油管或接头漏油,油箱中无燃油,燃油滤清     

Recent progress in vacuum-ultraviolet polarization modulation spectroscopy using polarizing undulator at the TERAS BL5 beamline

Polarization modulation spectroscopy using an Onuki-type undulator is a useful technique for circular dichroism study in the vacuum-ultraviolet region. We have been developing the vacuum-ultraviolet circular dichroism (vuv-CD) spectroscopy in TERAS BL5 beamline at AIST. This paper describes recent improvements in our instrumentation and methods of analysis to achieve precise and absolute measurements. The CD signal is usually accompanied by experimental artifacts, and elimination of all possible artifacts is the key issue for making reliable measurements. After improving beamline optical system, light flux monitor, and undulator operation method, the base line shift of the CD spectrum is suppressed less than 3x10(-4). Sample manipulation and data processing procedures are also described and absolute CD spectrum can be obtained even for linear anisotropic sample. These progresses lead to more quantitative comparison of experimental with calculation on vuv-CD spectrum.     

Invited review article: technology for attosecond science

We describe a complete technological system at Imperial College London for Attosecond Science studies. The system comprises a few-cycle, carrier envelope phase stabilized laser source which delivers sub 4 fs pulses to a vibration-isolated attosecond vacuum beamline. The beamline is used for the generation of isolated attosecond pulses in the extreme ultraviolet (XUV) at kilohertz repetition rates through laser-driven high harmonic generation in gas targets. The beamline incorporates: interferometers for producing pulse sequences for pump-probe studies; the facility to spectrally and spatially filter the harmonic radiation; an in-line spatially resolving XUV spectrometer; and a photoelectron spectroscopy chamber in which attosecond streaking is used to characterize the attosecond pulses. We discuss the technology and techniques behind the development of our complete system and summarize its performance. This versatile apparatus has enabled a number of new experimental investigations which we briefly describe.     

辉光放电清洗在同步辐射光束线上的应用

同步辐射光束线上存在的碳污染是影响光束线特别是软X光束线传输效率的重要原因,污染的生成与镜箱腔壁上存在有少量的油有关。为了获得更加洁净的真空室,通过辉光放电对镜箱真空室壁进行清洗,力争从源头上减少光学元件碳污染的产生。设计并搭建了一套应用在同步辐射光束线镜箱上的辉光放电清洗系统,并研究了装置在不同真空度下辉光的伏安特性。利用四极质谱对辉光放电前后及过程中镜箱内的残气进行分析。研究得出,真空室表面残留油分子的初步裂解产物主要是分子量为69的粒子。通过辉光放电清洗,真空室内残存的微量油大分子的(分子量为39,41,43,55,57,69,71)减少幅度达到50%。辉光放电清洗对真空腔体内表面油分子有明显的去除效果。本文研究的内容对于减少光束线站特别是软X射线光束线上碳污染具有重要意义。     

超高真空大截面差分系统的设计

本文提出了超高真空大截面差分系统的分析计算方法,并对北京正负电子对撞机同步辐射X射线光刻光束线的差分抽气系统进行了计算与设计。     

Soft x-ray scattering facility at the Advanced Light Source with real-time data processing and analysis

We present the development and characterization of a dedicated resonant soft x-ray scattering facility. Capable of operation over a wide energy range, the beamline and endstation are primarily used for scattering from soft matter systems around the carbon K-edge (～285 eV). We describe the specialized design of the instrument and characteristics of the beamline. Operational characteristics of immediate interest to users such as polarization control, degree of higher harmonic spectral contamination, and detector noise are delineated. Of special interest is the development of a higher harmonic rejection system that improves the spectral purity of the x-ray beam. Special software and a user-friendly interface have been implemented to allow real-time data processing and preliminary data analysis simultaneous with data acquisition.     

The electron spectro-microscopy beamline at National Synchrotron Light Source II: a wide photon energy range, micro-focusing beamline for photoelectron spectro-microscopies

A comprehensive optical design for a high-resolution, high-flux, wide-energy range, micro-focused beamline working in the vacuum ultraviolet and soft x-ray photon energy range is proposed. The beamline is to provide monochromatic radiation to three photoelectron microscopes: a full-field x-ray photoelectron emission microscope and two scanning instruments, one dedicated to angle resolved photoemission spectroscopy (μ-ARPES) and one for ambient pressure x-ray photoelectron spectroscopy and scanning photoelectron microscopy (AP-XPS/SPEM). Microfocusing is achieved with state of the art elliptical cylinders, obtaining a spot size of 1 μm for ARPES and 0.5 μm for AP-XPS/SPEM. A detailed ray tracing analysis quantitatively evaluates the overall beamline performances.     

梦之线光栅单色器温度起伏对能量漂移的影响

为了确保光栅单色器温度起伏引起的能量漂移不影响光束线的表观能量分辨率,建立了单色器高精度的恒温环境。结合上海光源梦之线设计,根据光栅衍射方程推导出单色器温差与能量漂移之间的关系;据此设计了沿光束方向温度起伏较小的单色器恒温环境,测试了温度控制系统不同条件下的长期温度稳定性,并通过长时间多次测量氮气K边吸收谱的方法,得到了相应的能量漂移。结果显示:温度控制系统未启动的情况下,棚屋内最大温度变化约为0.62K,测得的能量漂移约为49 meV;温度控制系统使用独立冷水机时,最大温度变化约为0.20 K,相应的能量漂移约为17meV。实验表明,建立的单色器恒温环境满足设计要求,使得单色器温差引起的能量漂移对梦之线表观能量分辨率的影响得到有效控制。     

Scanning photoelectron microscope for nanoscale three-dimensional spatial-resolved electron spectroscopy for chemical analysis

In order to achieve nondestructive observation of the three-dimensional spatially resolved electronic structure of solids, we have developed a scanning photoelectron microscope system with the capability of depth profiling in electron spectroscopy for chemical analysis (ESCA). We call this system 3D nano-ESCA. For focusing the x-ray, a Fresnel zone plate with a diameter of 200 μm and an outermost zone width of 35 nm is used. In order to obtain the angular dependence of the photoelectron spectra for the depth-profile analysis without rotating the sample, we adopted a modified VG Scienta R3000 analyzer with an acceptance angle of 60° as a high-resolution angle-resolved electron spectrometer. The system has been installed at the University-of-Tokyo Materials Science Outstation beamline, BL07LSU, at SPring-8. From the results of the line-scan profiles of the poly-Si/high-k gate patterns, we achieved a total spatial resolution better than 70 nm. The capability of our system for pinpoint depth-profile analysis and high-resolution chemical state analysis is demonstrated.     

A hyperthermal energy ion beamline for probing hot electron chemistry at surfaces

An ultrahigh vacuum ion beamline and chamber have been assembled to produce hyperthermal (<400 eV) energy ions for studying hot electron chemistry at surfaces. The specific design requirements for this modified instrument were chosen to enable the exposure of a metal-oxide-semiconductor (MOS) device to monoenergtic, well-collimated beams of alkali ions while monitoring both the scattered beam flux and the device characteristics. Our goal is to explore the role that hot electrons injected toward the MOS device surface play in the neutralization of scattered ions. To illustrate the functionality of our system, we present energy-resolved spectra for Na+, K+, and Cs+ ions scattered from the surface of a Ag(001) single crystal for a range of incident energies. In addition, we show MOS device current-voltage characteristics measured in situ in a new rapid-turnaround load lock and sample translation stage.