A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Courant, E. D.

Paper Title Page
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.

THPAS103 Design of a Thin Quadrupole to be Used in the AGS Synchrotron 3723
  • N. Tsoupas, L. Ahrens, R. Alforque, M. Bai, K. A. Brown, E. D. Courant, J. W. Glenn, H. Huang, A. K. Jain, W. W. MacKay, M. Okamura, T. Roser, S. Tepikian
    BNL, Upton, Long Island, New York
  Funding: Work supported by the US Department of Energy

The AGS synchrotron employs two partial helical snakes* to preserve the polarization of the proton beam during acceleration in the AGS. The effect of the helical snakes on the beam optics is significant at injection energy, with the effect greatly diminishing early in the acceleration cycle. In order to compensate for the effect of the snakes on the beam optics, we have introduced eight compensation quadrupoles in straight sections of the AGS at the proximity of the partial snakes. At injection the strength of these eight quads is set at a high value but ramped down to zero when the effect of the snakes diminishes. Four of the compensation quadrupoles had to be placed in very short straight sections therefore had to be 'thin' with a length of ~30 cm. The 'thin' quadrupoles were laminated and designed to minimize the strength of the dodecoupole harmonic. The thickness of the lamination was also calculated** to keep the ohmic losses generated by the eddy currents in the laminations below an acceptable limit. Comparison of the measured and calculated harmonics will be presented and the ohmic losses due to the eddy currents, as a function of time during rumping will be discussed.

* H. Huang, et al., Proc. EPAC06, (2006), p. 273.** OPERA computer code. Vector Fields Inc.