第三代同步辐射光源储存环支撑组件振动控制研究

第三代同步辐射光源对束流轨道稳定性要求很高, 上海光源是一台在建的第三代光源, 束流位置稳定度要求达到微米乃至亚微米级. 地基振动会使储存环磁聚焦结构中的各种元件发生机械振动引起随时间变化的束流闭合轨道畸变, 影响束流轨道稳定性. 上海光源场地振动幅值大, 需要研究措施控制机械组件的振动. 阻尼减振是一种有效的振动控制方法, 针对上海光源储存环机械组件, 作者设计了一种阻尼减振方案. 试验结果表明, 该方案能有效地控制机械组件的振动. 这对于保证上海光源的束流稳定性要求有积极意义.     

第四代同步辐射光源物理设计与优化

近十年来,世界上开始大力发展第四代同步辐射光源——衍射极限储存环光源。目前我国正在建设或立项建设两台第四代同步辐射光源:高能同步辐射光源和合肥先进光源。从储存环磁聚焦结构设计与优化、束流注入与集体效应等方面,对第四代同步辐射光源的物理设计与优化进行了介绍;对国际范围内第四代储存环光源装置的研制情况进行了介绍。     

合肥光源储存环温度监测系统

温度是影响电子束轨道稳定的重要因素之一,大多数加速器都需要为其建立完备的冷却恒温系统及相应的监测系统.描述了合肥光源基于EPICS(Experimental Physics and Industrial ControlSystem)分布式控制系统开发的温度监测系统的硬件结构、软件设计、测试结果及其历史数据库.经实际运行表明,该系统能很好满足与温度相关的机器研究和运行的需要.     

Biomolecular solution X-ray scattering at the National Synchrotron Light Source

In recent years there has been a growing interest in the application of X-ray scattering techniques to biomolecules in solution. At NSLS, a new undulator-based beamline, X9, has been constructed to address the oversubscribed user demand for X-ray scattering. Beamline X9 has the capability to perform small/wide-angle X-ray scattering (SAXS/WAXS) all in one single instrument. This is accomplished by utilizing a vacuum sample/detector chamber that is an integral part of the SAXS scattering flight path. This vacuum chamber allows a WAXS detector to be positioned at a close distance from the sample, while not interfering with scattered X-rays at small angles from reaching the SAXS detector. A regular training program, the X9 workbench, has also been established to allow users to become familiar with beamline X9 for solution X-ray scattering.     

三维控制网技术在BEPCⅡ储存环中的应用研究

介绍了加速器准直测量控制网的特点及BEPCⅡ储存环的控制网, 给出了基于全站仪和激光跟踪仪的三维控制网技术在该工程中的研究和应用情况, 联合利用这两种仪器, 采用三维测量方式建立了一个高精度的测量控制网, 着重分析了三维控制网的优缺点及增加全站仪观测值后对控制网精度的贡献, 并指出三维控制网技术具有较好的应用前景.     

Refurbishment of a used in‐vacuum undulator from the National Synchrotron Light Source for the National Synchrotron Light Source‐II ring

The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS‐II. There were four in‐vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini‐gap undulator (MGU‐X25, to be renamed IVU18 for NSLS‐II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS‐II. At the time of construction, IVU18 was a state‐of‐the‐art undulator designed to be operated as a cryogenic permanent‐magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS‐II ring, the transition region was redesigned. The control system was also updated to NSLS‐II specifications. This paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning.     

Diamond anvil cell radial x-ray diffraction program at the National Synchrotron Light Source

During the past decade, the radial x-ray diffraction method using a diamond anvil cell (DAC) has been developed at the X17C beamline of the National Synchrotron Light Source. The detailed experimental procedure used with energy dispersive x-ray diffraction is described. The advantages and limitations of using the energy dispersive method for DAC radial diffraction studies are also discussed. The results for FeO at 135?GPa and other radial diffraction experiments performed at X17C are discussed in this report.     

Advancements and Application of Microsecond Synchrotron X-ray Footprinting at the Advanced Light Source

The method of synchrotron X-ray protein footprinting (XF-MS) is used to determine protein conformational changes, folding, protein-protein and protein-ligand interactions, providing information which is often difficult to obtain using X-ray crystallography and other common structural biology methods [1 G. Xu and M.R. Chance, Chemical Reviews 107, 3514–3543 (2007).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]–3 V.N. Bavro, Biochem Soc Trans 43, 983–994 (2015).[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]]. The technique uses comparative in situ labeling of solvent-accessible side chains by highly reactive hydroxyl radicals (?OH) in buffered aqueous solution under different assay conditions. In regions where a protein is folded or binds a partner, these ?OH susceptible sites are inaccessible to solvent, and therefore protected from labeling. The ?OH are generated by the ionization of water using high-flux-density X-rays. High-flux density is a key factor for XF-MS labeling because obtaining an adequate steady-state concentration of hydroxyl radical within a short irradiation time is necessary to minimize radiation-induced secondary damage and also to overcome various scavenging reactions that reduce the yield of labeled side chains.     

Sirius: A 5BA Low-Emittance Lattice with Superbends for the New Brazilian Synchrotron Light Source

Starting in the late 1980s and into the 1990s, Brazil developed its own technology for the production of synchrotron light, designing and building UVX, a light source based on a 1.37 GeV electron storage ring with a circumference of 93 m and natural emittance of 100 nm.rad [1 Liu, L., Jahnel, L. and Tavares, P. The LNLS UVX2 soft X-ray source. Proc. of the EPAC 92 Conference. Berlin. pp.450–452.  [Google Scholar]]. Over more than 15 years of routine operation for users, the expansion capabilities for this light source, either in terms of new beamlines or upgrades to its accelerators, have reached fundamental limits that can no longer be overcome. The first discussions about a new low-emittance light source for Brazil started in 2006 among the scientific and accelerator communities during the 16^th LNLS Annual Users Meeting. In November 2008, a decision by the Brazilian Federal Government was taken to fund preliminary studies for this new source, leading to the final decision to fund the whole project in 2011. The proposed new synchrotron light source, Sirius, is based on a 3 GeV electron storage ring with a circumference of 518 m, a natural emittance of 0.28 nm.rad, and a total of 20 straight sections, of which 18 are for insertion devices. The new facility is being built at the same LNLS site as shown in Figure 1.