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Shi, J.

Paper Title Page
MOPP155 Superconducting RF Deflecting Cavity Design and Prototype for Short X-ray Pulse Generation 913
 
  • J. Shi, H. Chen, C.-X. Tang
    TUB, Beijing
  • G. Cheng, G. Ciovati, P. Kneisel, R. A. Rimmer, G. Slack, L. Turlington, H. Wang
    Jefferson Lab, Newport News, Virginia
  • D. Li
    LBNL, Berkeley, California
  • A. Nassiri, G. J. Waldschmidt
    ANL, Argonne, Illinois
 
  Deflecting RF cavities are proposed to be used in generating short x-ray pulses (on ~1-picosecond order) at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL)* using a novel scheme by Zholents**. To meet the required deflecting voltage, impedance budget from higher order, lower order and the same order modes (HOM, LOM and SOM) of the APS storage ring, extensive deflecting cavity design studies have been conducted with numerical simulations and cavity prototypes. In this paper, we report recent progress on a single cell S-band (2.8-GHz) superconducting deflecting cavity design with waveguide damping. A copper and a niobium prototype cavity were fabricated and tested, respectively to benchmark the cavity and damping designs. A new damping scheme has been proposed which provides stronger damping to both HOM and LOM by directly coupling to a damping waveguide on the cavity equator.

* A. Nassiri, private communication, 2007
** A. Zholents et al. NIM, 1999, A425:385-389.

 
MOPP156 Fabrication and Low Power Testing of an L-band Deflecting Cavity for Emittance-exchange at ANL 916
 
  • J. Shi, H. Chen, W.-H. Huang, C.-X. Tang, D. Tong
    TUB, Beijing
  • W. Gai, C.-J. Jing, K.-J. Kim, J. G. Power
    ANL, Argonne, Illinois
  • D. Li
    LBNL, Berkeley, California
 
  An L-Band RF deflecting cavity has been built at Tsinghua University for a planned transverse-to-longitudinal emittance exchange experiment at Argonne National Laboratory (ANL). The deflector is a 1.3-GHz, 3-cell cavity operated in a TM110-like mode that delivers a deflecting voltage of 3.4 MV. In this paper, we review the cavity design and present detail of the fabrication, cold testing and tuning progress. Cell radii were left undercut to account for simulation errors, which yielded a higher frequency in the first bench measurement but removed by the final tuning on the lathe. Field distribution on axis was measured using the ‘‘bead-pull'' method and tuned to balance in the 3 cells.