Author: Cheng, W.X.
Paper Title Page
TUBL1 NSLS-II BPM and Fast Orbit Feedback System Design and Implementation 316
  • O. Singh, B. Bacha, A. Blednykh, W.X. Cheng, J.H. De Long, A.J. Della Penna, K. Ha, Y. Hu, B.N. Kosciuk, M.A. Maggipinto, J. Mead, D. Padrazo, I. Pinayev, Y. Tian, K. Vetter, L.-H. Yu
    BNL, Upton, Long Island, New York, USA
  The National Synchrotron Light Source II is a third generation light source under construction at Brookhaven National Laboratory. The project includes a highly optimized, ultra-low emittance, 3 GeV electron storage ring, linac pre-injector and full energy booster synchrotron. The low emittance requires high performance beam position monitor systems, providing measurement to better than 200 nm resolution; and fast orbit feedback systems, holding orbit to similar level of orbit deviations. The NSLS-II storage ring has 30 cells, each deploying up to 8 RF BPMs and 3 fast weak correctors. Each cell consists of a "cell controller", providing fast orbit feedback system infrastructure. This paper will provide a description of system design and summarize the implementation and status for these systems.  
slides icon Slides TUBL1 [5.225 MB]  
WEPC08 Vibration Measurement and its Effect on Beam Stability at NSLS2 674
  • W.X. Cheng, A.K. Jain, S. Krinsky, S.K. Sharma, C.J. Spataro
    BNL, Upton, Long Island, New York, USA
  Vibration measurements have been carried out at NSLS2. The floor has more than 100nm RMS vertical motion during workdays (>1Hz). This motion reduces to 30nm RMS during night and weekends. Traffic on the nearby expressway is considered to be the major source of ground motion. Weather (wind) and utility system induced vibrations are other possible factors on floor motion. Vibrations have been measured at various locations, like the tunnel and experiment floor, HXN long beamline satellite building floor, high stability BPMs, Quadrupole magnets etc. Assume a typical un-correlated motion of Quadrpole magnets of 100nm, beam orbit jitter is around 4-7 microns. Fast orbit feedback will control the orbit stability within 10% of beam size.  
WEPC09 Performance of NSLS2 Button BPM 678
  • W.X. Cheng, B. Bacha, B.N. Kosciuk, S. Krinsky, O. Singh
    BNL, Upton, Long Island, New York, USA
  Several types of button BPMs are used in NSLS2 complex. Coaxial vacuum feedthroughs are used to couple the beam induced signal out. The feedthroughs are designed to match the external transmission line and electronics with characteristic impedance of 50 Ohm. Performances of these BPM feedthroughs are presented in this paper.