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Lin, F.

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TUODKI05 Overcoming Depolarizing Resonances in the AGS with Two Helical Partial Snakes 748
  • H. Huang, L. Ahrens, M. Bai, K. A. Brown, C. J. Gardner, J. W. Glenn, F. Lin, A. U. Luccio, W. W. MacKay, T. Roser, S. Tepikian, N. Tsoupas, K. Yip, K. Zeno
    BNL, Upton, Long Island, New York
  Funding: Work performed under contract No. DE-AC02-98CH1-886 with the auspices of the DoE of United States, and support of RIKEN(Japan).

Dual partial snake scheme has provided polarized proton beams with 1.5*1011 intensity and 65% polarization for RHIC spin program. To overcome the residual polarization loss due to horizontal resonances in the AGS, a new string of quadrupoles have been added. The horizontal tune can now be set in the spin tune gap generated by the two partial snakes, such that horizontal resonances are avoided. This paper presents the accelerator setup and preliminary results.

slides icon Slides  
TUPMS073 Dispersion Tolerance Calculation for NSLS-II 1341
  • W. Guo, S. Krinsky, F. Lin
    BNL, Upton, Long Island, New York
  The approach for the proposed National Synchrotron Light Source II to reach small transverse emittances is to deploy damping wigglers. In the ideal lattice the dispersion is zero in the straight sections, therefore the damping wigglers supply only damping effect. In reality the residual dispersion can be generated by the lattice errors, trim dipoles, and the insertion devices. We will discuss dispersion introduced by different sources and calculate the tolerances. Possible correction schemes will also be presented.  
THPAS011 Investigation of Residual Vertical Intrinsic Resonances with Dual Partial Siberian Snakes in the AGS 3534
  • F. Lin, S.-Y. Lee
    IUCF, Bloomington, Indiana
  • L. Ahrens, M. Bai, K. A. Brown, E. D. Courant, J. W. Glenn, H. Huang, A. U. Luccio, W. W. MacKay, T. Roser, N. Tsoupas
    BNL, Upton, Long Island, New York
  Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, No. DE-FG02-92ER40747, NSF PHY-0552389, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA)

Two partial helical dipole snakes were found to be able to overcome all imperfection and intrinsic spin resonances provided that the vertical betatron tunes were maintained in the spin tune gap near the integer 9. Recent vertical betatron tune scan showed that the two weak resonances at the beginning of the acceleration cycle may be the cause of polarization loss. This result has been confirmed by the vertical polarization profile measurement, and spin tracking simulations. Possible cure of the remaining beam polarization is discussed.