In this paper, a quad-slits interferometer using visible light is designed to measure the transverse beam size of Hefei Light Source-II (HLS-II). According to the beam parameters of the B7 source point, the preliminary simulation results are obtained by using the Synchrotron Radiation Workshop (SRW) code. Furthermore, the core parameters of the quad-slits components in the interferometer are optimized. Among, the optimum slits-separations of dH and dV are acquired to be 6.0 mm and 10.0 mm, respectively. It is shown that the simulated results are consistent with the theoretical values, which provides a reference value for performing the related experiments in the future.
Observation and Analysis of Island Phenomenon in the Storage Ring Light Source
373
Y.K. Zhao, S.S. Jin, P. Lu, B.G. Sun, L.L. Tang, J.G. Wang, F.F. Wu, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People’s Republic of China
In the previous experimental investigations and measurements using the radio-frequency (RF) phase modulation method to study the longitudinal beam characteristics of the Hefei Light Source-II (HLS-II), we found that the longitudinal bunch distributions under different modulation frequencies and amplitudes have great difference. In order to further explore island phenomenon and better understand beam motion associated with external RF phase modulation, the streak camera is exploited to effectively observe the longitudinal bunch profile and distribution in single-bunch filling mode. In addition, the dependence between island size, bunch dilution effect and modulation frequency are also discussed in detail. This is meaningful for researching the impact of RF noise on longitudinal beam dynamics, beam manipulation, and machine maintenance and debugging.
Design and Simulation of the Coupling Structure for Single Resonant Cavity Bunch Length Monitor
377
H.X. Tuo, P. Lu, Q. Luo, B.G. Sun, F.F. Wu, T.Y. Zhou
USTC/NSRL, Hefei, Anhui, People’s Republic of China
The measurement of the bunch length can better realize the monitoring of the beam, because the bunch length is one of the important longitudinal parameters of the beam. In this paper, a new single-cavity bunch length monitor is proposed, whose coupling structures consist of two kinds of filters. One is a low pass filter, the other is a band pass filter. The coaxial low-pass filter is used to couple out lowfrequency signals, and the band-pass filter is used to couple higher-frequency signals. According to the beam characteristics of the National Synchrotron Radiation Laboratory (NSRL)based on the tunable infrared laser energy chemistry research large-scale experimental device (FELiChEM), we perform simulation in CST. The simulation results show that the monitor can measure the bunch length of the FELiChEM device very well, and the simulation measurement error is less than 2%.
R.Z. Wu, P. Lu, B.G. Sun, L.L. Tang, Y.G. Wang, F.F. Wu, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People’s Republic of China
In order to improve the performance of Hefei Light Source (HLS-II), it is necessary to study various problems of nonlinear beam dynamics in the storage ring, so as to optimize the beam filling mode and injection mode, and then improve the intensity and brightness of HLS-II. In beam dynamics, bunch-by-bunch can provide detailed information of beam bunches and help beam researchers to study the problems of beam bunches deeper. Therefore, HLS-II diagnostics group has developed an on-line bunch-by-bunch three-dimensional measurement system based on high bandwidth and high speed oscilloscope.
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