双丝型同步辐射光束位置监测器的参数设计

双丝型同步辐射光束位置监测器(PBPM)基于光电子发射原理,通过光敏丝探测同步辐射的强度.在扫描模式下可以方便地获得光束的强度分布情况,在静止状态时则可以通过两根丝上光电流大小的相对变化对同步辐射光束的位置进行实时监测.本文介绍了这种双丝型PBPM的原理、设计、参数优化及误差分析,及其在北京同步辐射装置上的应用情况.     

合肥光源基于虚拟仪器技术的束流诊断系统

介绍了合肥光源利用虚拟仪器技术构成的束流诊断系统,包括基于GPIB总线构成了储存环直流流强测量系统,基于VXI总线构成了束流闭轨测量系统,基于PCI总线构成了束流横向截面测量系统,基于网络化虚拟仪器技术构成了在线束团长度测量系统和同步光位置测量系统.软件采用Lab-VIEW编程,极大地减轻了开发的工作量.     

Libera Photon在合肥光源同步光位置测量系统中的应用

合肥光源新引进了IT公司的新一代光位置信号处理器Libera Photon,其采用嵌入式EPICS IOC,极大地提高了数据的传输效率,经测试,该处理器的分辨率好于0.07 μm。同时,自主研制开发了相配套的时钟分配器以及远程软件控制程序,并将新同步光位置信号处理系统用于原有的双丝型光位置探测器进行了初步的应用研究,测试得到的同步光位置信息与相近的BPM Q8E所测得的束流位置信息变化趋势一致,说明Libera Photon能够很好地进行同步光位置信息的测量。     

Synchrotrons radiation stability measurement and improvement

In the 3rd generation synchrotron light source,beside the orbit,air disturbance and ground vibration also could affect the position stability of photon beam in synchrotrons radiation measurement.In the condition of implementation of orbit feedback system at SSRF,the measured position stability of photon beam in synchrotrons radiation measurement station was presented in this paper.And then the improvement methods of position stability of photon beam were discussed.Finally the measured result was shown when the designed feedback system is implemented to improve the position stability of photon beam.     

合肥光源波荡器光束线光位置检测器

研制了合肥光源波荡器光束线刀片型光位置检测器。在不同波荡器狭缝下,对刀片电极的光电流进行了测量,并对其进行了标定,得到了灵敏度和同步光中心位置,如在狭缝为40mm时,水平方向和垂直方向的灵敏度分别为0.0015mm^-1 和0.8522mm^-1。为了改进刀片型光位置检测器,给出了一种交错刀片型光位置检测器的设计,该检测器将狭缝为40mm时的水平灵敏度提高到0.551mm^-1。     

Turn-by-turn system and its primary experiment at HLS

During the Phase II project of NSRL, a turn by turn BPM (Beam Position Monitor) system is proposed for storage ring diagnostics which engages log-ratio electronics circuit to measure machine properties of the HLS (Hefei Light Source) storage ring. The log-ratio processor works at 408 MHz, twice the RF frequency of HLS. Modern logarithmic amplifiers with wide dynamic range, great bandwidth, good logarithmic conformance, and low cost are attractive for beam position measurements. Injection kicker and the stripline-electrode resonant exciting methods are used to excite beam for nonlinear beam dynamics and phase space studies of stored beam. Up to 2 seconds of data acquisition is ensured. In this paper we present the performance of each component and preliminary test results of the turn-by-turn BPM system.     

3D Position Information Extraction of Refilled Charge during Injection Process of Electron Storage Ring

The injection process of electron storage ring is a special transient process. The mismatch between the injector and the storage ring can be evaluated online by studying the 3D merging of refilled charge and stored charge. For the next-generation light source, it can lay a technical foundation for building a diagnostic system. The beam instrumentation group of the Shanghai Synchrotron Radiation Facility developed a 3D bunch-by-bunch diagnostic system based on button pick-up signal and high-speed acquisition boards to measure the beam transverse position and longitudinal phase. Extracting the 3D position information of the refilled charge during the injection process is the critical issue in this system. The charge-weighted average method was proposed to extract the transverse position and the proportional coefficient method was proposed to extract the longitudinal phase. The transverse betatron oscillation and longitudinal synchrotron oscillation of the refilled charge were analyzed. 3D position information of the refilled charge and several dynamic parameters of ring, such as longitudinal maximum oscillation amplitude, initial arrival time and synchrotron damping time, can be extracted during the user operation mode, which provides a strong toolkit for accelerator physics.     

电子储存环注入过程中补注电荷的三维位置信息提取

电子储存环的注入过程是特殊的瞬态过程,研究补注电荷和储存电荷的三维位置融合过程可在线评估注入器与储存环的匹配度,也可为下一代光源诊断系统的搭建奠定技术基础。目前,上海同步辐射光源束流检测组研发了一套基于纽扣电极拾取信号和高速采集板卡的三维逐束团诊断系统,可精确测量逐束团三维位置。注入过程中补注电荷的三维位置信息可通过电荷加权平均法和比例系数法分别提取。通过对补注电荷横向betatron振荡和纵向同步振荡的分析,可原位提取betatron振荡振幅、同步振荡振幅、初始到达时间、同步振荡阻尼时间等多个动态参数,不需提供特别的机器研究时间,为储存环动力学研究提供了有力工具。     

The measurement of electron beam transverse sizes by synchrotron radiation interferometry for HLS Ⅱ

In order to improve accuracy of electron beam transverse sizes measurement,the vertical and horizontal synchrotron radiation light interferometers have been designed to measure beam transverse sizes for the upgrade project of Hefei Light Source(HLS II).In this paper,the light intensity distributions of the interferogram are descussed,and parameters of the interferometers are optimized.The interferograms are simulated under MATLAB. Taking integrations of two-dimensional interferogram intensity,normalized one-dimensional interference intensities distribution of the vertical and horizontal interferogram are obtained.The two curves are fitted to compare the beam transverse sizes with the designed sizes,and this verifies the feasibility of this method.Finally,several factors that affect the beam sizes measurement are discussed.     

合肥光源超导扭摆磁铁模式下线性光学参数补偿

合肥光源是1台专用真空紫外光源，为拓展同步辐射用户可用光范围，在储存环上安装了1台6T的超导扭摆磁铁。超导扭摆磁铁给储存环光学参数带来很大扰动，造成工作点漂移和β函数畸变。最初，在补偿工作点漂移后，成功地存储了束流并产生了硬X射线，但该运行模式下束流寿命短，严重影响其它实验线站的实验工作。在合肥光源二期工程中，重新进行了超导扭摆磁铁补偿计算，在不改变目前储存环磁铁和电源的基础上，同时补偿工作点漂移和β函数畸变，大幅度地改善了束流寿命。     

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。     

Simulation of storage ring injection of HLS Ⅱ

The Hefei light source(HLS) has been upgraded into HLS II, with increased brightness and stability. In this paper, the new injection system is described. Elegant program is used to simulate the particles motion in 6D phase space. In the process of tracking simulation of electrons, the system tolerances and magnet errors are introduced. Influences to the injection efficiency from beam injection deviation are studied. These provide important reference for realizing the Top-up injection.     

上海同步辐射光源工作点稳定性研究

上海同步辐射光源（SSRF）是一台第3代高性能同步辐射装置,已稳定运行超过10年。储存环的线性光学模型稳定是光源稳定运行的基础。工作点反馈系统可实时地校正工作点,并间接地以降维的方式反馈难以在线测量到的线性光学函数。工作点反馈系统在SSRF的稳定运行验证了此方法的可行性,该反馈系统不仅使得工作点稳定度显著提升,也使得束流发射度、注入效率以及束流寿命等重要参数的稳定度得到大幅提升。衍射极限储存环光源是现阶段被广泛研究和建设的新一代同步辐射光源,工作点反馈系统也将发挥更重要的作用。本文分析电子储存环线性光学函数和工作点的稳定性,回顾SSRF工作点反馈系统的实际运行情况,介绍工作点反馈系统在SSRF衍射极限环lattice（SSRF-U）的模拟。工作点反馈在SSRF的实际运行情况和在SSRF-U的模拟结果显示,该系统可将工作点稳定在±0.001范围内,可满足储存环光源稳定运行和线性差耦合共振圆束斑模式对工作点稳定度的需求。     

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。     

New CAMAC based data acquisition and beam control system for Lund nuclear microprobe

A new CAMAC based data acquisition system has been installed at the Lund Nuclear Microprobe facility. This paper reports on the development and present status of the data acquisition system. The system is a true multiparameter CAMAC based system with fast Fera bus readout and in crate memory buffer. The user interface is based on Sparrow Kmax software for a Power Macintosh platform. The system read out and tag the event data with position on-line, which make fast on-line monitoring of spectra or element maps possible.Simultaneously, all data can be saved event by event for off-line analysis. The beam scanning part is software controlled through a timed D/A converter, this allows fast scanning of the beam. With a CCD-camera and video card the area to be analysed could be defined directly from the image, and the sample position can be moved. Any kind of irregular scan patterns could be defined.     

合肥光源的工作点测量系统

合肥 8 0 0MeV电子储存环的工作点测量系统采用扫频激励法进行工作点测量 ,它由条带束流位置检测器、180 0 的魔T、混频器、带扫频信号输出的频谱分析仪、功率放大器和束流激励电极等构成。该系统的测量精度约为 1× 10 4 。利用该系统进行了机器的校正色品测量 ,给出了工作点和色品的测量结果。     

合肥光源注入过程中束流负载效应和束流强度限制

根据储存环高频系统束流负载理论，研究计算了合肥光源注入过程中高频系统的大失谐角工作模式和调谐工作模式。综合考虑两种模式利弊，给出了更为灵活的注入模式。对于合肥光源，只要新高频系统参数设置合理，束流可顺利注入积累到设计值300mA以上。     

PSD位置测量系统在波荡器磁场测量中的应用

位置敏感探测器(Position Sensitive Detector,PSD)是一种基于横向光电效应(x和y方向)的光电位置敏感器件,可直接探测到入射光斑的能量中心位置,在波荡器磁测中可用于获得霍尔探头测量过程中的横向位置变化。为了在狭小或封闭空间内实现对波荡器(尤其是真空内波荡器)磁场进行高精度的测量,我们设计并搭建了测试系统,对导轨直线度(x和y方向)进行了测量。实验结果表明,该位置测量系统具有5μm的测量精度,可以满足霍尔探头在波荡器磁测过程中的位置精度要求。     

冲击磁铁误差对注入过程的影响

简要说明合肥同步辐射光源（ＨＬＳ）的储存环新注入系统,分析由于冲击磁铁的误差而产生的非理想凸轨以及对注入过程的影响。针对ＨＬＳ的三种运行模式进行计算机模拟,从而确定冲击磁铁的误差极限。     

滤光片及X射线二极管响应面均匀性研究

介绍了用于软X光能谱测量的滤光片及X射线二极管能量应均匀性研究。实验利用北京同步辐射装置3WIB束线,流强40－80mA的运行条件,在100－1600eV能区对滤光片及X射线二极管（XRD）作能响曲线标定。重点对C滤片及Al阴极XRD的灵敏面作能响面均匀性研究,最后给出响应面均匀性测量结果及计算分析。