Development of the Prototype for Measuring Beam Position and Orbit Tilt Based on Cavity BPM for the SHINE
J. Chen, F.Z. Chen
SSRF, Shanghai, People’s Republic of China
S.S. Cao
SARI-CAS, Pudong, Shanghai, People’s Republic of China
Y.B. Leng
USTC/NSRL, Hefei, Anhui, People’s Republic of China
In recent decades, the high-gain free-electron lasers (FELs) based on linear accelerator has been successfully developed around the world. Advanced beam diagnostics and feedback technology is one of the key factors to further improve the performance of such facilities. Both the beam position deviation and orbit tilt will weaken the interaction between electron beam and photon beam in the undulator, and affected the FEL radiation performance severely. According to the physical requirements of the SHINE, this paper proposes a method based on the measurement results of a single cavity BPM, which can simultaneously achieve the in-suit measurement of beam position deviation and orbit tilt, thus opening up a new way to improve the efficiency of FEL radiation. The working principle, the development of the verification prototype and the preliminary beam experiments will also be presented in this paper. Under the bunch charge of 100 pC, the beam experiment results show that the prototype has a resolution of better than 13.3¿rad for the beam orbit tilt measurement, which can be applied to the SHINE after optimization.
A Novel Cavity BPM Electronics for SHINE Based on RF Direct Sampling and Processing
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L.W. Lai, S.S. Cao, X.Q. Liu, Y.M. Zhou
SARI-CAS, Pudong, Shanghai, People’s Republic of China
J. Chen
SSRF, Shanghai, People’s Republic of China
R. Meng
SINAP, Shanghai, People’s Republic of China
Funding:Work supported by The National Science Foundation of China (Grant No.12175293). Youth Innovation Promotion Association, CAS (Grant No. 2019290) A RF direct sampling beam signal processor has been developed in SSRF. It mainly consists of four channels RF direct sampling ADCs and a SoC FPGA. The ADC is 9GHz bandwidth and 2.6GHz sampling rate. A prototype of RF module contains band pass filter, low noise ampli-fier and step attenuator has been designed for SHINE cavity BPM system. Then a novel cavity BPM electronic including the processor and the RF module has been built for SHINE. The performance of the electronic has been analyzed and evaluated in lab. The amplitude relative error is 2.0×10-4,which is better than the required 1×10-3 on cavity BPM system. The phase error is 14fs, also bet-ter than the requirement of RF BAM system. The algorithm and the implementation in FPGA have been introduced. Corresponding author: lailw@sari.ac.cn
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