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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Application of Wavelet Algorithm in Tune Measurement
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X. Yang
SINAP, Shanghai, People’s Republic of China
F.Z. Chen, L.W. Lai
SSRF, Shanghai, People’s Republic of China
X. Yang
UCAS, Beijing, People’s Republic of China
Tune is a very important parameter for storage ring of advanced synchrotron radiation facilities. At present, fast Fourier transform (FFT) is the core algorithm of the beam spectrum analysis used in tune measurement. Taking into account the nonlinear effect in the accelerator, tune changes during the process of storage ring injection and booster energy upgrading. However, the Fourier method is used to analyse the global sampling point, and the ability to distinguish the local variation of the tune in the sampling time is poor. This paper leads wavelet analysis method as the core algorithm into beam spectrum analy-sis method, further analyses the change of the tune with beam amplitude in sampling time, and compares this new algorithm with the traditional Fourier method. New ex-perimental results and corresponding analysis for the data from SSRF will be introduced in this paper.
J. Wan
SINAP, Shanghai, People’s Republic of China
F.Z. Chen, J. Chen, B. Gao, Y.B. Leng, K.R. Ye, L.Y. Yu, W.M. Zhou
SSRF, Shanghai, People’s Republic of China
SHINE is a high repetition rate XFEL facility, based on an 8 GeV CW SCRF linac, under development in Shanghai. In order to meet the requirements of measuring the beam profile of SHINE in real time and without obstruction, a new diagnostic instrument, wire scanner has been designed. This paper mainly describes the design of wire scanner in SHINE, and some simulation results are also shown and discussed.
