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Chou, P.J.

Paper Title Page
WEPCH049 Closed Orbit Correction of TPS Storage Ring 2029
 
  • H.-J. Tsai, H.-P. Chang, P.J. Chou, C.-C. Kuo, G.-H. Luo, M.-H. Wang
    NSRRC, Hsinchu
 
  A 3 GeV synchrotron storage ring is proposed in Taiwan to serve the synchrotron light users, especially for the x-ray community. The ring consists of 24 double-bend cells with 6-fold symmetry and the circumference is 518.4 m. The designed natural emittance with slightly positive dispersion in the straight sections is less than 2 nm-rad. This low emittance lattice structure needs strong quadrupoles and sextupoles and the closed orbit distortions are sensitive to the alignment errors in the quadrupoles and sextupoles as well. The closed orbit distortions due to tolerable magnetic errors are simulated and the correction scheme is proposed. Using singular value decomposition method, the closed orbit distortions are corrected and corrector strengths as well as the residual closed orbit distortions are obtained.  
WEPCH050 Correction of Vertical Dispersion and Betatron Coupling for the TPS Storage Ring 2032
 
  • H.-J. Tsai, H.-P. Chang, P.J. Chou, C.-C. Kuo, G.-H. Luo, M.-H. Wang
    NSRRC, Hsinchu
 
  A proposed 3 GeV Taiwan Photon Source (TPS) is a low emittance (1.7 nm-rad) medium energy storage ring with 24 DBA cells. The vertical emittance due to betatron coupling and spurious vertical dispersion generated by the magnet errors and off-center orbits in sextupoles and quadrupoles are analyzed. The sensitivities due to magnetic alignment errors are estimated. Using the SVD method, the result of global vertical dispersion and betatron coupling correction is presented.  
THPCH062 Collective Effects in the Storage Ring of Taiwan Photon Source 2928
 
  • P.J. Chou, C.H. Kuo, C.-C. Kuo, M.-H. Wang
    NSRRC, Hsinchu
 
  A new 3- 3.3 GeV synchrotron light source is proposed and named the Taiwan Photon Source (TPS). The TPS design has a natural horizontal emittance less than 2 nm-rad and low emittance coupling, which results in small beam size. The nominal bunch length in TPS storage ring is much shorter compared to the existing Taiwan Light Source, that makes the issue of parasitic heating more significant. Several small-gap insertion devices are planned to provide extremely bright x-ray photon beam. Those design features have impacts on collective beam instabilities. A preliminary study of collective effects in the TPS storage ring is presented.  
THPCH097 Commissioning of the Digital Transverse Bunch-by-bunch Feedback System for the TLS 3020
 
  • K.H. Hu, J. Chen, P.J. Chou, K.-T. Hsu, S.Y. Hsu, C.H. Kuo, D. Lee, C.-J. Wang
    NSRRC, Hsinchu
  • A. Chao
    SLAC, Menlo Park, California
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
  • W.-T. Weng
    BNL, Upton, Long Island, New York
 
  Multi-bunch instabilities degrade the beam quality leading to increased beam emittance, energy spread or even to beam loss. The feedback system is used to suppress multi-bunch instabilities due to resistive wall of the beam ducts, cavity-like structures and trapped ions. A new digital transverse bunch-by-bunch feedback system was commissioned at the Taiwan Light Source recently, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance compared with the old system, enhances damping for transverse instability at high current, and as a result, top-up operation was achieved. In this new system, a single feedback loop simultaneously suppresses both the horizontal and vertical multi-bunch instabilities. The feedback system employs the latest generation FPGA feedback processor to process bunch signals. Memory installed to capture up to 250 msec bunch oscillation signal has included the considerations for system diagnostic and should be able to support various beam physics study.  
THPCH098 FPGA-based Longitudinal Bunch-by-bunch Feedback System for TLS 3023
 
  • C.H. Kuo, J. Chen, P.J. Chou, K.-T. Hsu, S.Y. Hsu, K.H. Hu, W.K. Lau, D. Lee, C.-J. Wang, M.-H. Wang, M.-S. Yeh
    NSRRC, Hsinchu
  • M. Dehler
    PSI, Villigen
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
 
  A FPGA Based Longitudinal Bunch-by-Bunch Feedback System for TLS is commissioning recently to suppress strong longitudinal oscillation. The system consists of pickup, Bunch oscillation detector, FPGA based feedback processor borrow form the design of Spring8. Modulator converts the correction signal to the carrier frequency and longitudinal kicker which was re-designed form SLS' and working at 1374 MHz. The feedback processor is based upon latest generation FPGA feedback processor to process bunch signals. The memory capture is up to 250 msec bunch oscillation signal. The software and hardware design are also included for system diagnostic and support various beam physics study. Preliminary commission result will be summaried in this report.  
THPLS063 Nonlinear Beam Dynamics of TPS 3430
 
  • H.-P. Chang, P.J. Chou, C.-C. Kuo, G.-H. Luo, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
 
  A design study of 3.0 GeV high performance low emittance storage ring Taiwan Photon Source has been conducted recently The natural emittance of the storage ring can be as low as 1.7 nm-rad in our design and its lattice structure is a 24-cell double bend achromat type with circumference of 518.4 m, which will be located in the existing NSRRC site in Hsinchu. The strong focusing requires strong aberration correction with nonlinear sextupole magnets. The distribution of the sextupoles and number of families are studied to ensure a good dynamic aperture. The nonlinear effects in both betatron and synchrotron motions are investigated. Nonlinear beam dynamics effects in the presence of magnetic field imperfections as well as the insertion devices are simulated. The physical aperture limitations are included in the study too, and the Touschek lifetime is calculated. The tracking data are analyzed using frequency map analysis method and corresponding beam dynamics behavior can be revealed more precisely.  
THPLS067 Vertical Beam Size Control in TLS and TPS 3442
 
  • C.-C. Kuo, H.-P. Chang, J.-R. Chen, P.J. Chou, K.-T. Hsu, G.-H. Luo, H.-J. Tsai, D.-J. Wang, M.-H. Wang
    NSRRC, Hsinchu
  • A. Chao
    SLAC, Menlo Park, California
  • W.-T. Weng
    BNL, Upton, Long Island, New York
 
  Vertical beam size control is an important issue in the light source operations. The horizontal-vertical betatron coupling and vertical dispersion were measured and corrected to small values in the TLS 1.5 GeV storage ring. Estimated beam sizes are compared with the measured values. By employing an effective transverse damping system, the vertical beam blow-up due to transverse coherent instabilities such as the fast-ion beam instability was suppressed and as a result, the light source is very stable. In NSRRC we are designing an ultra low emittance 3-GeV storage ring and its designed vertical beam size could be as small as a few microns. The ground and mechanic vibration effects, and coherent instabilities could spoil the expected photon brightness due to blow-up of the vertical beam size if not well taken care of. The contributions of these effects to vertical beam size increase will be evaluated and the counter measures to minimize them will be proposed and reported in this paper.  
THPLS068 Design of Taiwan Future Synchrotron Light Source 3445
 
  • C.-C. Kuo, H.-P. Chang, C.-T. Chen, P.J. Chou, H.J. Jhao, G.-H. Luo, H.-J. Tsai, M.-H. Wang
    NSRRC, Hsinchu
 
  We report updated design works for a new 3-3.3 GeV synchrotron light source with a high performance and low emittance storage ring, called Taiwan Photon Source (TPS). With its natural horizontal emittance less than 2 nm-rad and low emittance coupling, TPS will be able to provide an extremely bright photon beam to the demanding users, especially the x-ray community. The lattice type of the TPS is a 24-cell DBA structure and the circumference is 518.4 m. We present the lattice design, the accelerator physics issues and its performances.