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%.     

束流位置探头用于束团电荷量测量的数值仿真研究

加速器常用的束流位置探头为电磁耦合型,其输出信号包括束流位置信息和束团电荷量信息.本文采用数值仿真方法研究探头电极和信号与束流位置之间的关系,基于Matlab开发一个用于仿真计算探头电荷量标定系数的软件包.对上海光源储存环束流位置探头的仿真结果表明,探头流强标定系数在2.5 mm半径内差值小于千分之二,在此精度范围内可认为流强标定系数为常数.     

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.     

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...     

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.     

SSRF-X射线小角散射实验站数据采集系统

采用LabVIEW对上海光源(SSRF)X射线小角散射(SAXS)实验站数据采集系统进行了设计,实现了对气体探测器和电离室的电子学系统实验参数设置、实验数据采集和实验结果的保存功能.经实验测试,证实了该系统的正确性和完整性.     

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.     

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%.     

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.     

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.     

SSRF数字化电源巡检系统的设计

开发了SSRF数字电源巡检系统,实现远程巡检与本地巡检两种模式,采用LabVIEW软件开发平台设计了简单美观的用户界面,两种硬件结构在数字化电源巡检用户软件界面上不需修改.远程巡检用于模拟数字化电源与中央控制室间远程监控通讯的调试,及时排查远程通讯或电源的故障;本地巡检可同时检测18台数字化电源,长期(24 h)进行故障状态监视,并通过Excel或text记录与保存,进行电源性能指标验收.两种巡检模式已用于SSRF的数字化电源巡检.     

上海光源全局束流诊断数据仓库开发

上海光源已建成的束流诊断系统可满足光源的日常运行和机器研究需要。但由于缺少有效的事件触发处理机制,无法保存并分析运行期间突发的全局轨道扰动、BPM故障和DCCT噪声等异常现象。为解决以上问题,本文在现有束测系统的基础上开发了基于Soft IOC的全局束流诊断数据仓库。数据仓库通过在线监测加速器和束测系统的运行状况,在发现异常现象时及时发出触发信号并存储相关数据进行分析。运行结果表明,数据仓库能有效检测加速器和束测系统异常,并可用于生成束测设备置信度指标,为进一步优化束测系统和提高光源运行性能提供有效依据。     

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.     

上海光源数字化束流位置信号处理器测试平台研制

数字化束流位置信号处理器(Digital Beam Position Monitor Processor,DBPM)是上海光源自主研发作为束流位置监测(Beam Position Monitor,BPM)的主要设备。针对DBPM电子学处理器产品化测试需求开发了一套基于MATLAB和程控技术的自动化测试平台,用于处理器批量测试验收和性能评估。平台使用Agilent MXG信号源和一分四功分器模拟4路真实探头信号,经过处理器采集处理后被上位机接收。测试仪器的设置和实验数据的获取,整个系统是基于客户端和服务器架构实现的。采用物理实验与工业控制系统(Experimental Physics and Industrial Control System,EPICS)的通道访问Lab CA接口实现数据的实时采集。目前该测试平台已经成功应用于大连自由电子激光装置和上海软X射线自由电子激光装置的DBPM处理器验收测试,处理器幅频响应曲线,不同衰减下模数变换器(Analog to Digital Converter,ADC)噪声水平测试、衰减步长一致性、通道间串扰及信噪比测试结果均达到设计指标。     

Beam trip diagnostic system at SSRF

In this paper we report the design and realization of beam trip diagnostic system at Shanghai Synchrotron Radiation Facility (SSRF).The system can find out the first fault signal in the key operation signals related to the RF system by analyzing the time sequence,also it can decide which trips occurs first among the three superconducting RF stations.All the states of monitored signals in a time period ahead and behind beam trip are recorded.The results are compared with those from other diagnostic tools at SSRF.The work is of help in improving reliability of the superconducting RF system and stability of the storage ring operation.     

SSRF磁测数据管理与应用软件系统的开发

介绍了上海同步辐射装置即上海光源工程(简称SSRF)磁测数据的管理与应用软件系统的研发情况。     

Simulations for optimization of SSRF BPM

The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by using the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of resonance in its cavity like structure either is harmful to beam or limits the performance of BPM itself, and should be reduced to tolerable levels. The calculated results show that there are three main peaks in the impedance spectrum of the SSRF BPM prototype, and two of which are above the limit. After lots of simulations for different shapes of the BPM button, a new structure of SSRF BPM have been found, and there is only one main peak, which is under the limit, in the impedance spectrum. Its output signal also meets the requirement.     

Development of the bunch-by-bunch beam position acquisition system based on BEEcube

In this paper, we report the development of a bunch-by-bunch beam position acquisition system.Through a wideband synthesizer of PLL, the system realizes synchronous clock of bunch signal. Based on the highperformance FPGA hardware DAQ environment, fourchannel raw data of beam signal can be achieved. Test results in the SSRF storage ring show that the system can obtain beam position of single bunch with the resolution of10 lm and multi-bunch instability can be observed.     

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.     

Phase control system for SSRF linac

The design of phase control system in Shanghai Synchrotron Radiation Facility (SSRF) linac is presented in this paper. And digital phase detecting algorithm, the key for phase control system, is fully described. The testing results for phase control system in 100MeV linac are discussed in detail.