Bunch-length measurement at a bunch-by-bunch rate based on time–frequency-domain joint analysis techniques and its application

作     者：Hong-Shuang Wang Xing Yang Yong-Bin Leng Yi-Mei Zhou Ji-Gang Wang Hong-Shuang Wang;Xing Yang;Yong-Bin Leng;Yi-Mei Zhou;Ji-Gang Wang

作者机构：Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201800China University of Chinese Academy of SciencesBeijing 100049China National Synchrotron Radiation LaboratoryUniversity of Science and Technology of ChinaHefei 230026China Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China 

出 版 物：《Nuclear Science and Techniques》 (核技术（英文）)

年 卷 期：2024年第35卷第4期

页      面：165-175页

核心收录：

学科分类：08[工学] 0827[工学-核科学与技术] 082701[工学-核能科学与工程] 0702[理学-物理学] 

基　　金：supported by the National Key R&D Program(No.2022YFA1602201)。 

主　　题：Bunch-by-bunch diagnostic Bunch-length measurement Synchronous phase measurement Joint time–frequency-domain analysis Longitudinal instability 

摘      要：This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage rings.This technique uses the time–frequency-domain joint analysis of the bunch signal to obtain bunch-by-bunch and turn-by-turn longitudinal parameters,such as bunch length and synchronous phase.The bunch signal is obtained using a button electrode with a bandwidth of several gigahertz.The data acquisition device was a high-speed digital oscilloscope with a sampling rate of more than 10 GS/s,and the single-shot sampling data buffer covered thousands of turns.The bunch-length and synchronous phase information were extracted via offline calculations using Python scripts.The calibration coefficient of the system was determined using a commercial streak camera.Moreover,this technique was tested on two different storage rings and successfully captured various longitudinal transient processes during the harmonic cavity debugging process at the Shanghai Synchrotron Radiation Facility(SSRF),and longitudinal instabilities were observed during the single-bunch accumulation process at Hefei Light Source(HLS).For Gaussian-distribution bunches,the uncertainty of the bunch phase obtained using this technique was better than 0.2 ps,and the bunch-length uncertainty was better than 1 ps.The dynamic range exceeded 10 ms.This technology is a powerful and versatile beam diagnostic tool that can be conveniently deployed in high-energy electron storage rings.