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%.     

A modeling GUI for accelerator physics of the storage ring at SSRF

In this paper, we report a MATLAB-based GUI tool, bodgui, which integrates functions of lattice editor,linear match, and nonlinear optimization, and visualized tracking functions for beam optics design. A user can switch his/ber design procedures one to another. Flexibilities are provided for adjusting or optimizing the lattice settings in commissioning or operation of the accelerators. The algorithm of the linear match and nonlinear optimization, and the GUI windows including the main functions and running status, are presented. The SSRF storage ring was employed as a test lattice. Several optics modes designed and optimized by the GUI tools were used for commissioning the storage ring. Functions of bodgui tool are machine-independent, and it can be well applied to modern light sources being built in other parts of the world.     

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.     

上海光源X射线针孔相机控制系统设计

采用美国NI公司的PXI-7344运动控制卡对衰减片进行控制;通过RS232协议控制小孔四维移动平台和相机二维移动平台的运动,实现对小孔位置、倾角和相机位置的调节;NI公司的PXI-8252板卡用于1394相机的图像采集.所有控制功能均有机地集成于LabVIEW界面中,实现各部件的协调配合运动,并通过EPICSShar...     

A real-time beam loss monitoring system for storage ring of SSRF

In this paper we report the real-time beam loss monitoring (BLM) system at the storage ring of SSRF.The BLM-XS detectors and Ethernet data acquisition system are used in this system.Some applications and experiments of the BLM system are also presented.The BLM system provides dynamic information of beam loss for the storage ring,and is helpful to ensure the facility commissioning,investigate the problems of machine,optimize the machine parameters and further increase the beam lifetime.     

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.     

Monitoring the charge bunch-by-bunch for the SSRF storage ring:Development and application

Bunch charge uniformity controlling is very important for top-up operation of the storage ring. In order to monitor filling pattern and measure the bunch charge precisely, a PXI waveform digitizer-based data acquisition system has been developed to retrieve bunch charge information from BPM pickup signals. An effective sampling rate is extended to 400 GHz by waveform rebuilding technology, which overlays multi-turn data into single turn with real time sampling rate of 8 GHz. An on-line evaluation indicates that resolution and linearity of the charge measurement are better than 0.5% at input range of 0.5-12 nC.     

Improving Touschek lifetime and synchrotron frequency spread by passive harmonic cavity in the storage ring of SSRF

Beam lifetime of a synchrotron is dominated by Touschek scattering.In the beamline Phase Ⅱ project of Shanghai synchrotron radiation facility,a passive third harmonic cavity is to be installed for bunch lengthening and instability suppressing.In this paper,the beam dynamics of the cavity is investigated.The parameters of passive operation are optimized to cancel the slope of RF voltage and lengthen the bunches.The Touschek lifetime increases are estimated for optimum and non-optimum voltage flattening.A tolerance of the operation is studied in case that there is a shift on detuning angle.The effect caused by reduction in harmonic voltage generated by lengthened bunch distribution is also estimated using iteration method.An increase in synchrotron frequency spread due to nonlinearity of the voltage giving to the bunch is found by using tracking simulation.This spread can help in damping coupled bunch instability through Landau damping.     

Development of button-type pickup for SSRF ring

In building Shanghai Synchrotron Radiation Facility(SSRF), in order to reduce or eliminate the unnecessary sources of beam motion, the precise and stable beam position measurement system in the feedback system was required. In this study, we focused on theoretical analysis of the electrode of beam position monitor(BPM).Simulations, including analytic derivations of the propagation impedance and the distribution inductance, were performed. The BPM was designed based on the results and the acceptance measurements of the impedance and the inductance by using the time domain reflection(TDR) with a network analyzer. It has been proved in years of operations that the BPM system meets the requirement of the resolution of sub-micron.     

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...     

Analysis of transmission efficiency of SSRF electron beam transfer lines

1 Introduction The Shanghai Synchrotron Radiation Facility (SSRF) [1], as one of the national important scientific projects, is a third-generation intermediate energy, low-emittance and high-brightness light source under construction. The SSRF accelerator complex consists of a 150 MeV pre-injector (linear accelerator), a 3.5 GeV full-energy injector[2] (booster synchrotron and beam transfer lines) [3], a 3.5 GeV storage ring [4,5] and a series of synchrotron radiation beam lines and exp…     

上海光源插入件光束线白光狭缝设计

上海光源是第三代同步辐射装置,第一期工程拟建造7条光束线中有5条选用插入件光源,其中,三条由波荡器(Undulator)引出,两条由扭摆器(Wiggler)引出。插入件光源产生高功率同步辐射,会给插入件光束线部件设计带来极大的挑战。为此,我们为插入件光束线设计了新型L形白光狭缝,本文主要介绍了该白光狭缝设计。     

Correction of integrated multipoles of five IDs in SSRF

Five of the seven Phase I beamlines of Shanghai Synchrotron Radiation Facility (SSRF) are based on insertion devices (IDs), which include two wigglers, one elliptically polarized undulator (EPU), and two in-vacuum undulators. There were some inevitable field integral errors in manufacturing the IDs, and these would affect performance of the storage ring. The integrated multipoles were corrected by using the magic fingers technique. In this paper, we report the correction method based on the simulated-annealing algorithm. The results show that the integrated multipole components were corrected to meet the design specifications.     

Current status and progresses of SSRF project

The Shanghai Synchrotron Radiation Facility （SSRF）, a third generation light source, comprises a 3.5GeV electron storage ring, a full energy booster, a 150 MeV linac, and seven beamlines in Phase I of the project. Beginning at the end of 2004 with a groundbreaking ceremony, the accelerators were installed in ten months from November 2006, and were successfully tested and commissioned in the past a couple of months. On December 21, 2007, storing electron beams in the storage ring was realized, and the first synchrotron radiations were observed three days later on the front-end of Beamline BL16B of the facility. Now, it runs 3 GeV 100 mA beams with a lifetime of 8-10 hours. Meanwhile, construction of the first seven beamlines （five ID beamlines and two bending magnet beamlines） is progressing on schedule.     

基于AT＆MCA的SSRF低能输运线上层应用软件设计

AT和MCA都是基于MATLAB的介于上层应用软件和底层加速器控制系统之间的加速器物理软件工具包.文章详细介绍了基于这两个软件包的SSRF低能输运线上层应用软件设计.离线及在线仿真测试以及SSRF低能输运线调束结果表明,该软件所有功能基本运行正常,软件通过EPICS与真实电源之间数据读写准确,计算结果与SSPF低能输运线各参数相符,匹配及轨道校正等功能在SS-RF低能输运线的调束工作中也起到了一定的作用.     

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.     

一个基于EPICS框架的EPU前端反馈系统

插入件是现代光源重要组成设备之一,其质量直接影响上海光源整体性能。由于建造和安装工艺的限制,插入件的磁场会对束流轨道稳定性产生影响。为降低对束流的扰动,在插入件电子束流入口和出口位置增加校正线圈实现自动补偿功能。因此我们设计了基于EPICS的插入件前端反馈系统,经测试,该前馈系统用户界面简洁,反馈控制功能完整可靠,实时性高,提高了束流的稳定性,为试验站稳定供光提供了保证。     

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.