B. Gao, S.S. Cao, Y.B. Leng
SSRF, Shanghai, People’s Republic of China
L.W. Lai, X.Q. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China
SSRF is currently working on the beam line phase-II project, which has moved toward laser/x-ray pump-probe experiments. In order to quantify the bunch pattern and charge purity of the probe pulse, a bunch purity monitor based on the time-correlated single-photon counting system has been installed. This system has very good time resolution of 22ps, and high dynamic range of more than seven orders of magnitude. In this paper, system setup, system evaluation and optimization process，a series of experimental studies and initial application will be described.
Beam Instrumentation System for Shanghai Soft X-ray FEL Test Facility
17
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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Upgrade and First Commissioning of Transverse Feedback System for SSRF
136
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.
Development of Abnormal Beam State Monitoring Processor on SSRF Storage Ring
223
L.W. Lai, Y.B. Leng, Y.B. Yan
SSRF, Shanghai, People’s Republic of China
An abnormal beam state monitoring processor has been developed on SSRF, which is based on the hardware of self-developed digital BPM processor. By applying digital signal processing algorithms in the on-board FPGA, the processor keeps monitoring the beam running state. Once abnormal event is detected, the processor will record the abnormal event type and store the turn-by-turn beam position data before and after the event for later analyzing. The abnormal events including beam loss and beam position jump.
Application of Wavelet Algorithm in Tune Measurement
268
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.
