Beam Instrumentation System for Shanghai Soft X-ray FEL Test Facility
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L.W. Lai, F.Z. Chen, J. Chen, J. Chen, W. Fang, C. Feng, B. Gao, R. Jiang, Y.B. Leng, Y.B. Yan, L.Y. Yu, R.X. Yuan, N. Zhang, W.M. Zhou, T. Shen
SSRF, Shanghai, People’s Republic of China
S.S. Cao, L.F. Hua
SINAP, Shanghai, People’s Republic of China
Shanghai Soft X-ray FEL (SXFEL) test facility was designed and built to demonstrate EEHG and HGHG schemes and verify key technologies for the future hard X-ray FEL facility (SHINE). After three years commissioning 8.8 nm FEL radiation with peak power of 1 MW had been achieved at the end of 2019. The design, fabrication, commissioning and operation of BI system including Stripline-BPM, Cavity-BPM, screen monitor, bunch length monitor, beam arrival monitor, bunch energy monitor, will be introduced in this paper. Several lessons learned during design stage and beam commissioning stage will be addressed as well.
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J. Chen, S.S. Cao, F.Z. Chen, B. Gao, L.W. Lai, Y.B. Leng, T. Wu, X.Y. Xu, R.X. Yuan, Y.M. Zhou
SSRF, Shanghai, People’s Republic of China
Precise bunch charge measurement is the fundamental of charge feedback, beam lifetime measurement, beam loss monitor, as well as the basis of the related interlocking work. Beam position monitor (BPM) is often used for high-precision bunch charge measurement due to its superior performance. In this paper, the pros and cons of different types of BPM for measurement of bunch charge in storage ring and free electron laser (FEL) will be discussed. The related simulations, beam experiment and signal processing methods are also mentioned. The beam experiments results show that the relative bunch charge resolution of the Button BPM can reach 0.02％ in SSRF, 0.073％ and 0.021％ of the SBPM and CBPM in SXFEL, respectively. Besides, based on the method of beam experiments, we systematically studied the position dependence of BPM pickup and related compensation algorithms for high-precision bunch charge measurement.
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S.S. Cao
Private Address, Zhangjiang, Shanghai, People’s Republic of China
R. Jiang, Y.B. Leng, R.X. Yuan
SSRF, Shanghai, People’s Republic of China
SHINE (Shanghai High repetition rate XFEL aNd Extreme light facility) is designed to be an extremely high-performance hard X-ray free-electron laser facility located at Zhangjiang, Shanghai. As one of the key parameters of the facility, the resolution of the beam position measurement in the undulator section is required to be under 200 nm at a low bunch charge of 100 pC and better than 10 um at 10 pC. To achieve this, a pre-study based on cavity beam position monitors is under development. Four sets of cavity monitors with different frequencies or load quality factors have been designed and are now manufactured by four different companies. It aims to select the cavity with the best performance and select the most capable company. This paper will briefly introduce the motivation, cavity design considerations, and cold test results.
Upgrade and First Commissioning of Transverse Feedback System for SSRF
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N. Zhang, B. Gao, L.W. Lai, R.X. Yuan
SSRF, Shanghai, People’s Republic of China
To be a part of the transverse feedback system upgrade plan in SSRF PHASE II project, a set of Dimtel feedback processors was installed to replace the previous set. In the commissioning, the ability of supressing the trans-verse oscillation was tested and evaluated, also, beam diagnostics and control tools of the processors was used for injection transients analysis, tune tracking and bunch cleaning. The results of the commissioning and data analysis will be presented in this paper.
