Beam based alignment of the SSRF storage ring

• Published in: Chinese physics C Vol. 33; no. 4; pp. 301 - 305
• Main Author: 张满洲 李浩虎 姜伯承 刘桂民 李德明
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.04.2009; Graduate University of Chinese Academy of Sciences,Beijing,100049,China%Shanghai Institute of Applied Physics,CAS,Shanghai,201800,China; Shanghai Institute of Applied Physics,CAS,Shanghai,201800,China
• Subjects: SSRF; 上海同步辐射装置; 储存环; 数据处理方法; 束流位置监测器; 管理系统; beam based alignment; static quadrupole modulation; SSRF
• ISSN: 1674-1137; 0254-3052; 2058-6132
• DOI: 10.1088/1674-1137/33/4/013

There are 140 beam position monitors （BPMs） in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment （BBA） method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.