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 

机构地区：[1]Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230026,China [4]Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201204,China

出　　处：《Nuclear Science and Techniques》2024年第4期165-175,共11页核技术（英文）

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

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.

关 键 词：Bunch-by-bunch diagnostic Bunch-length measurement Synchronous phase measurement Joint time–frequency-domain analysis Longitudinal instability 

分 类 号：TL594[核科学技术—核技术及应用]