数字化平均流强测量方法研究

平均流强测量可用DCCT或ICT探头,ICT探头有很强的抗电磁干扰能力,但测量精度不高.用高精度A/D转换器和等效采样测量算法使ICT探头组成的平均流强测量系统有较高的测量精度.本文主要介绍了基于ICT探头的平均流强测量系统、测量算法和实验室测试结果.     

SSRF储存环共架机构热-力耦合分析

上海同步辐射光源(SSRF)工程中,束流稳定性是提高SSRF性能指标的关键因素,影响束流稳定性的一个主要因素就是工作状态下温度变化引起的支架和磁铁的变形.本文以上海光源储存环共架机构为研究对象,采用参数化有限元法、借助有限元分析软件ANSYS WORKBENCH,对不同工况下的共架机构进行热-力耦合仿真,得出共架机构的温度场和应力场,为控制支架的稳定性进而保证上海光源束流稳定性提供依据.     

Filling patterns in the SSRF storage ring

<正>There are various filling patterns in a storage ring for the users' requirements and consideration of the machine performances,such as beam lifetime,instability and chamber heating.These effects have been experimentally studied in the SSRF storage ring for typical filling patterns.Some experiment results and general trends of observations discussed in this paper.The explanations of the results are given.     

Multi-bunch injection for SSRF storage ring

The multi-bunch injection adopted at Shanghai Synchrotron Radiation Facility(SSRF) increases the injection rate greatly, with much less injection time than that of single bunch injection. It reduces massively the beam failure time during users' operation and prolongs the pulsed injection hardware lifetime. In this paper, the scheme to produce multi bunches for the RF electron gun is described. The filling result and beam orbit stability for top up operation is discussed.     

Design of the SSRF storage ring magnet lattice

The Shanghai Synchrotron Radiation Facility (SSRF) is a proposed 3rd generation light source with 3.5 GeV in energy. It is composed of 20 DBA celis resulting in a ring that is about 10 nm-rad in emittance and 396 m in circumference, and provides 10 straight sections of 7.24 m and other 10 straight sections of 5.0 m for the inclusion of insertion devices, injection components and RF cavities. The lattice has high flexibility, and the tunes and beta func-tions can be easily adjusted within a wide range to meet the requirements for different operation modes, including high beta mode and hybrid beta mode with and/or without dispersion in straight sections. In this paper, the results of linear optics design and dynamic aperture study are presented.     

上海光源储存环直流流强监测系统设计

上海光源储存环调试运行需要一个分辨率达到微安量级的直流流强监测系统.为此设计完成的硬件系统包含一个Bergoz公司NPCT型探头、一个NI公司PXI总线数字电压表模块以及一个PXI总线的输入输出控制器.数据采集处理软件在LabVIEW平台上开发,与控制系统的接口通过EPICS Shated Memory IOCcore技术实现.实验室测试及仿真结果表明该系统直流流强测量分辨率可达2微安,束流寿命相对测量精度可望达到0.5%.     

Study of orbit stability in the SSRF storage ring

In this paper, analysis of the beam orbit stability and conceptual study of the dynamic orbit feedback in the SSRF storage ring are presented. It is shown that beam orbit position movement at the photon source points is smaller than the orbit stability requirements in horizontal plane, but exceeds the orbit stability requirements in vertical plane. A dynamic global orbit feedback system, which consists of 38 high-bandwidth air-coil correctors and 40 high-precise BPMs, is proposed to suppress the vertical beam orbit position movement. Numerical simulations show that this dynamic orbit feedback system can stabilize the vertical beam orbit position movement in the frequency range up to 100 Hz.     

上海光源储存环光子吸收器布局设计

电子束经过储存环弯转磁铁发生偏转时,产生总功率-435 kW的同步辐射光,其中仅有一小部分被引入光束线、实验站,其余须在储存环中被光子吸收器吸收处理,并准直引出光束.本文对上海光源(SSRF0储存环同步辐射光的处理方法进行了讨论,并介绍了光子吸收器的布局、结构、性能及运行状况.     

Effects of insertion device on SSRF storage ring

Shanghai Synchrotron Radiation Facility （SSP.F）, one of the third generation light sources, aims to produce high brightness and/or high flux X-ray source for users; therefore insertion devices （IDs） are important magnetic elements for SSRF. In this paper, the linear perturbations due to IDs toward its storage ring lattice, such as beta function distortions, tune shifts, emittance growths, and energy spreads are estimated by using analytical formulae, and the nonlinear effects from IDs, especially dynamic aperture, are simulated by using Racetrack code. The results show that （a） the reduction of dynamic aperture from single undulator is negligible, since electron beam energy of 3.5 GeV is high and ID＇s magnetic field is low, and the beta functions in the middle of straight sections, where ID is located, are well optimized; Co） however, the reduction from single wigglers, especially super-conducting wiggler, is visible, because of its higher magnetic field; （c） effects of each ID on emittance growths and energy spreads are less than 7%.     

上海光源储存环束流位置监测系统

本文简述了上海光源储存环位置测量系统的物理需求、基本设计思想以及软硬件结构,对其中采用的数字束流位置信号处理器、高精度纽扣型束流位置探头、信号传输网络等关键部件的研制、安装情况进行了详细介绍.该系统经一年调试优化现已投入日常运行,结果表明位置分辨率达到亚微米量级,优于上海光源设计要求.     

Calibration of the linear optics in the SSRF storage ring

Phase Ⅰ commissioning of the SSRF storage ring at 3.0 GeV was ended with encouraging results. Distortions and calibrations of the linear optics during the storage ring commissioning are discussed in this paper. The calibration procedure has reduced sextupole-additional focusing effects by minimizing closed orbit deviation and corrected quadrupole magnetic coefficients with the linear optics from closed orbit (LOCO) technique. After fitting the closed orbit response matrix, linear optics of the storage ring is substantially corrected, and the measured parameters agree well with the design. Four optics modes were commissioned, and relevant machine physics studies were carried out. Their results are summarized.     

上海光源储存环新注入方式

上海光源储存环的新工作模式和新装插入件会导致动力学孔径和注入效率的减小,传统的注入方式不再满足恒流注入要求。分别从改变注入方式和减小注入束流发射度两个角度解决注入对动力学孔径的需求。脉冲多极铁与凸轨相结合的注入方式可以将动力学孔径的要求降低到7 mm以下。利用斜四极铁在高能输运线上进行水平和垂直发射度互换可以将注入束流发射度降低到近1/10而降低注入点的束斑尺寸。两者都可以将注入效率提高到95%以上。二者在更小动力学孔径的情况下同时使用还可以减小脉冲多极铁的强度。     

上海光源储存环X-ray针孔相机系统设计

上海光源(SSRF)储存环X-ray针孔相机系统主要由X-ray引出前端、衰减片、小孔、靶片、相机、PXI控制器及图像采集等构成,数据采集处理软件在LabVIEW平台上开发,与控制系统的接口通过EPICS Shared Memory IOCcore技术实现。2009年8月开始的长时间在线运行证明引出前端是安全的,在300mA运行时,测量引出窗的最高温度≤36℃。该系统设计合理、性能稳定,可在线实时测量数十μm束团横向截面尺寸,从而实现3.9nm·rad发射度的测量。     

Lattice design and optimization of the SSRF storage ring with super-bends

In the near future,the Phase-Ⅱ beamline project of Shanghai Synchrotron Radiation Facility(SSRF)will be implemented and some dipoles in the storage ring will be replaced by high field dipoles(super-bend),so as to leave room for short straight sections.In this way,the brightness of the hard x-ray emitted from the super-bends can be enhanced,and more insertion devices can be installed.In this paper,super-bends of two lengths are discussed and the corresponding lattices are presented.     

高频噪声对上海光源储存环束流品质的影响

为了向用户提供高品质的同步辐射光,储存环束流应具有好的性能.储存环高频噪声的存在会影响到束流品质.本文基于DKW理论,研究了高频幅度噪声与相位噪声对束流能散度的影响,并分析了束团长度拉伸效应,以及对小间隙插入件U27上微聚焦光束品质的影响.模拟结果显示,位相噪声对束流品质以及辐射光品质的影响比较显著,且阶次越高的辐射光受高频噪声的影响越大.     

上海光源储存环真空数据检索系统

本文介绍一种基于Web的上海光源(SSRF)储存环真空数据库检索系统的设计与实现。该系统建立基于实验物理和工业控制系统(EPICS)真空数据的采集系统,用Channel Archiver存储真空规的压强读数、动态真空度、束流流强及束流寿命等数据到历史数据库中,可从不同联网计算机检索数据,建立一个合理有效的SSRF储存环真空数据共享平台,为设备和科研人员提供一个可用可靠的数据来源。     

SSRF储存环注入脉冲电源的设计

本文介绍了采用固态半导体放电开关实现的1.7 kV、10 kA的Septum电源和7.8 kV、3.7 kA的Kicker电源,详细分析了两台脉冲电源的电容器充电电源、脉冲放电开关、放电回路结构、热漂移校正等问题.原型样机的结果表明,其电流幅度稳定性都优于±0.1%,其他主要指标均可达到设计要求.     

SSRF储存环高频屏蔽波纹管的研制

建造中的上海光源即上海同步辐射装置(SSRF)储存环将采用内装高频屏蔽机构的波纹管——高频屏蔽波纹管。SSRF采用了由接触指和弹簧指构成的双指型屏蔽机构。屏蔽机构的关键设计参数是由SSRF壁电流和壁电场所决定的指间接触力和高次模决定的相邻接触指间的缝隙宽度和长度。对高频屏蔽波纹管进行了热测试和阻抗测试。测试结果表明,接触力、缝隙和阻抗都适合SSRF的实际运行条件。     

Feedforward compensation of the insertion devices effects in the SSRF storage ring

The lattice of the Shanghai Synchrotron Radiation Facility(SSRF) storage ring was upgraded in the Phase-II beamline project, and thus far, 18 insertion devices(IDs) have been installed. The IDs cause closed-orbit distortions, tune drift, and coupling distortions in the SSRF storage ring, all of which are significant issues that require solutions. In this study, an ID orbit feedforward compensation system based on a response matrix using corrector coils was developed, and it was applied to all co...