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Yang, L.

Paper Title Page
WEPEA076 NSLS-II Lattice Optimization with Non-zero Chromaticity 2663
 
  • W. Guo, S. Krinsky, L. Yang
    BNL, Upton, Long Island, New York
 
 

Chromaticity is usually set to non-zero value at the third generation light sources to cure the intensity induced instabilities. It is effective in suppressing the beam centroid oscillation; however, it is repeatedly reported that the beam lifetime decreases significantly when chromaticity goes up. This is probably due to the crossing of resonance lines by the enlarged tune footprint. In this paper we optimize the NSLS-II lattice at different positive chromaticity settings. The tune footprint is adjusted to fit in the stable region divided by the strong resonance lines. Tracking results show that we can maintain a lifetime similar to that of the zero-chromaticity lattice solutions.

 
WEPEB026 Prototype of Beam Commissioning Environment and its Applications for NSLS-II 2740
 
  • G.B. Shen, L. Yang
    BNL, Upton, Long Island, New York
  • M.R. Kraimer
    ANL, Argonne
 
 

A fundamental infrastructure of software framework for beam commissioning for NSLS-II storage ring is in development. It adopts client/server model, and consists of various servers for data communication and management. Based on this structure, some physics applications are developed to satisfy the requirements of day-1 beam commissioning. This paper describes our status of infrastructure development and its applications.

 
THPE055 Linear Optics Measurements and Corrections Using AC Dipole In RHIC 4644
 
  • G. Wang, M. Bai, L. Yang
    BNL, Upton, Long Island, New York
 
 

We report recent experimental results on linear optics measurements and corrections using ac dipole. In RHIC 2009 run, the concept of the SVD correction algorithm is tested at injection energy for both identifying the artificial gradient errors and correcting it using the trim quadrupoles. The measured phase beatings were reduced by 30% and 40% respectively for two dedicated experiments. In RHIC 2010 run, ac dipole is used to measure beta* and chromatic beta function. For the 0.65m beta* lattice, we observed a factor of 3 discrepancy between model and measured chromatic function in the yellow ring.

 
WEPEA070 Status of the Low Emittance Upgrade of the Advanced Light Source 2645
 
  • C. Steier, B.J. Bailey, A. Biocca, A. Madur, H. Nishimura, G.J. Portmann, S. Prestemon, D. Robin, S.L. Rossi, F. Sannibale, T. Scarvie, D. Schlueter, W. Wan, L. Yang
    LBNL, Berkeley, California
 
 

The Advanced Light Source is one of the earliest 3rd generation light sources. With an active upgrade program it has remained competitive over the years. The latest in a series of upgrades is a lattice upgrade project that was started in 2009. When it will be completed, the ALS will operate with a horizontal emittance of 2.2 nm and an effective emittance of 2.6 nm. Combined with the high current of 500 mA and the small vertical emittance the ALS already operates at this upgrade will keep it competitive for years to come. The presentation will present the status of the upgrade, including beam dynamics studies and lattice optimizations as well as the magnet design and status.

 
WEPEC042 A Possible Concept to Improve the Efficiency of the Very Low Beta SC Accelerating Structure 2980
 
  • L. Yang
    Peking University, School of Physics, Beijing
  • X.Y. Lu
    PKU/IHIP, Beijing
 
 

This paper introduce a possible solution to improve the efficiency of the very low beta SC accelerating structure, via extending the gaps number of 4-gap interdigital QWR by doubling its stems number. The new cavity is a 8-gap QWR, which is comprised of two parallel TEM resonant lines operating in opposing phase from each other. It maintains the 4-gap QWR's good EM parameters and enables the use of demountable flange. The more important advantage is the potential improvement of efficiency. According to a preliminary estimation of longitudinal dynamics, the 8-gap QWR could stably accelerate heavy ion at the velocities 0.01<v/c<0.05.

 
WEPEC043 R&D of PKU Single Spoke Cavity 2983
 
  • Z.Y. Yao, C. Chang, J.K. Hao, F.S. He, Y.M. Li, L. Lin, K.X. Liu, X.Y. Lu, S.W. Quan, B.C. Zhang, K. Zhao, F. Zhu
    PKU/IHIP, Beijing
  • L. Yang
    Peking University, School of Physics, Beijing
 
 

Spoke cavities have been developed and have apparent advantages for high current proton accelerator based on superconductivity at low and medium energy region. As the research and the technical reserve, Peking University has started the R&D program of single spoke cavity (SSC). The work is proposed to do beam load experiment on the HI-13 Tandem at CIAE. The maximum kinetic energy of proton beam is 26MeV, and the frequency of the chopper for superconducting is 150MHz. It leads us to the choice of a 450MHz and β=0.2 single spoke cavity. In this paper, the RF design, mechanical study, fabrication arts, tolerance analysis, and room temperature RF test is presented.