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Li, W.

Paper Title Page
WOAB010 BUNCH TRACING BY BUNCH BY BUNCH MEASUREMENT SYSTEM IN HLS 719
 
  • K. Zheng, W. Li, J.H. Liu, L. Liu, B. Sun, J.H. Wang, Y.L. Yang
    USTC/NSRL, Hefei, Anhui
 
  Funding: Supported by National Natural Science Project (10175063)

In this paper, we introduce a bunch tracing system which is based on a bunch-by-bunch (BxB) measurement system in Hefei Light Source (HLS), and present the analysis of the experiment results. Using an in-phase gate signal and a double balance mixer to control an external trigger of ADC, we test the reliability of the BxB system. By this system, we can trace all marked bunches in a set time slot or in manual burst mode. We can record all bunches’ data during the injection, ramping, wiggler excitation and normal operation, and provide a powerful facility for machine study.

 
RPAE076 The Commission of Hefei Light Source After Reconstruction 3967
 
  • H. Xu, H. He, W. Li, G. Liu, L. Liu, S. Shang, B. Sun, L. Wang
    USTC/NSRL, Hefei, Anhui
 
  After the new four-kicker injection bump system was mounted, it was found that the magnetic field of four–kicker magnet through the same pulse current is different each other, the reason is which the width of pulse magnet fields is not same, so the four-kickers can not form completely local bump, and produce large global orbit distortion,and lead to beam loss. At last we found that the films of ceramic chambers were not plated evenly. The new rf system have two low level control circle circuits, which are the frequency and amplitude automatic adjustment systems. Because the energy of injection electron beam is 200MeV, and radiation damping is weak, so the gain of amplitude circuit was adjusted to the small value not to disturb beam.The beam load is large,and Robinson instability happen easily, so the small detune angle is preset. The Octupoles were inserted in ring for damping instability, and over compensated chromaticity was adjusted.Superconductor wiggler bring the variation of beta function, and the beam life time decreased from 8 hours to about 3 hours. By adjusting the beta functions close to situation ago, the beam lifetime was improved.  
RPPT047 Development of Measurement and Transverse Feedback System at HLS 2974
 
  • J.H. Wang, H. He, W. Li, J.H. Liu, L. Liu, B. Sun, Y.L. Yang, K. Zheng, Z.R. Zhou
    USTC/NSRL, Hefei, Anhui
 
  In order to observe and cure coupled bunch (CB) instabilities caused by the high order modes (HOMs) of the RF cavity and the resistive wall impedance of the Ring vacuum chamber, which were ineluctable during the operation of the accelerator, an observer system characterized by bunch by bunch measurement of transverse ßoscillation and longitudinal synchrotron phase oscillation has been constructed and commissioned at Hefei Light Source (HLS); meanwhile a transverse bunch-by-bunch feedback system is under construction. The design and development of the systems, as well as diagnostics results of machine instabilities will be presented in this paper.  
RPPT048 HLS Turn-By-Turn System and Its Application 3022
 
  • J.H. Wang, W. Li, J.H. Liu, L. Liu, B. Sun, Y.L. Yang, K. Zheng
    USTC/NSRL, Hefei, Anhui
 
  Design and experimental application of the turn-by-turn system of Hefei Light Source (HLS) are presented in this paper. The front-end signal measurement adopts a log-ratio electronics circuitry. The system is designed to be capable of up to 2 seconds data acquisition. Injection kickers are used to excite beam for monitoring ß oscillation and damping rate. Some of experimental applications are also illustrated, in commission of both the upgraded injection system of HLS and the lower frequency feedback system. The results shows that in order to improve the accumulation of the injected beam, it is very necessary to investigate integral magnet fields equilibrium of injected system and proper measures to control restrain remnants ß-oscillation caused by the injected system error.  
RPPT049 Linear Optics Compensation of the Superconducting Wiggler in HLS 3037
 
  • L. Wang, G. Feng, W. Li, H. Xu, H. Zhang
    USTC/NSRL, Hefei, Anhui
 
  Hefei Light Source is a dedicated VUV light source. A superconducting wiggler magnet with 6 Tesla magnetic field was installed on the storage ring to generate hard X-ray radiation. With the compensation of tune shift due to insertion device, beam was successfully stored, but the beam lifetime was decreased much. In order to cure the lifetime, a simple hard-edge model of the wiggler was constructed in lattice simulation code and the compensation scheme was extensively studied again. Calculation showed that it is difficulty to localize the strong focusing effects from wiggler magnet. Then, a new scheme was brought forward and experimental result showed that it can restore the beam lifetime largely. As the application of LOCO method in HLS, a new compensation scheme was calculated by response matrix fitting, and the experimental result also presented in this paper.  
FPAT072 The Status of HLS Control System 3862
 
  • G. Liu, X. Bao, C. Li, W. Li, J. Wang, Xie. Xie, K. Xuan
    USTC/NSRL, Hefei, Anhui
  • J. Li
    DU/FEL, Durham, North Carolina
 
  HLS (Hefei Light Source) at NSRL (National Synchrotron Radiation Lab) consists of three parts: 200Mev Linac, transport line and 800Mev storage ring. The control system was upgraded based on EPICS (Experimental Physics and Industrial Control system) from 1999 to 2004. This paper will cover the experience of using PC-based hardware under EPICS, data archiving, and some high level tools for physics and operation use.