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Luccio, A. U.

Paper Title Page
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  
TUPMS083 Conceptual Design of the NSLS-II Injection System 1362
  • T. V. Shaftan, J. Beebe-Wang, J. Bengtsson, G. Ganetis, W. Guo, R. Heese, H.-C. Hseuh, E. D. Johnson, V. Litvinenko, A. U. Luccio, W. Meng, S. Ozaki, I. Pinayev, S. Pjerov, D. Raparia, J. Rose, S. Sharma, J. Skaritka, C. Stelmach, N. Tsoupas, D. Wang, L.-H. Yu
    BNL, Upton, Long Island, New York
  Funding: This work was supported by Department of Energy contract DE-AC02-98CH10886.

We present conceptual design of the NSLS-II injection system. The injection system consists of low-energy linac, booster and transport lines. We review the requirements on the injection system imposed by the storage ring design and means of meeting these requirements. We discuss main parameters and layout of the injection system components.

TUPAS085 RHIC Spin Flipper 1847
  • M. Bai, A. U. Luccio, Y. Makdisi, P. H. Pile, T. Roser
    BNL, Upton, Long Island, New York
  Funding: The work was performed under the auspices of the US Department of Energy.

Full spin flip in the presence of full Siberian snake has been achieved by using an rf dipole or solenoid as spin flipper at IUCF and COSY. This technique requires one to change the snake configuration to move the spin tune away from half integer. However, this is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. An new technique of achieving full spin flip with the spin tune staying at half integer is proposed. This paper presents the design of RHIC spin flipper along with simulation results.

TUPAS086 Snake Depolarizing Resonance Study in RHIC 1850
  • M. Bai, P. Cameron, H. Huang, A. U. Luccio, V. Ptitsyn, T. Roser, S. Tepikian
    BNL, Upton, Long Island, New York
  Funding: US Department of Energy, RIKEN(Japan), Renaissance Technologies Corp.(USA)

Snake depolarizing resonances due to the imperfect cancellation of the accumulated perturbations on the spin precession between snakes were observed at the Relativistic Heavy Ion Collider~(RHIC). During the RHIC 2005 and 2006 polarized proton runs, we mapped out the spectrum of odd order snake resonance at Qy=7/10. Here, Qy is the beam vertical betatron tune. We also studied the beam polarization after crossing the 7/10th resonance as a function of resonance crossing rate. This paper reports the measured resonance spectrum as well as the results of resonance crossing.

The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and RenaissanceTechnologies C orp.(USA)

TUODKI04 Accelerating Polarized Protons to 250 GeV 745
  • M. Bai, L. Ahrens, I. G. Alekseev, J. G. Alessi, J. Beebe-Wang, M. Blaskiewicz, A. Bravar, J. M. Brennan, K. A. Brown, D. Bruno, G. Bunce, J. J. Butler, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K. A. Drees, W. Fischer, G. Ganetis, C. J. Gardner, J. W. Glenn, T. Hayes, H.-C. Hseuh, H. Huang, P. F. Ingrassia, J. S. Laster, R. C. Lee, A. U. Luccio, Y. Luo, W. W. MacKay, Y. Makdisi, G. J. Marr, A. Marusic, G. T. McIntyre, R. J. Michnoff, C. Montag, J. Morris, P. Oddo, B. Oerter, J. Piacentino, F. C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, M. Wilinski, A. Zaltsman, A. Zelenski, K. Zeno, S. Y. Zhang
    BNL, Upton, Long Island, New York
  • D. Svirida
    ITEP, Moscow
  Funding: The work was performed under the US Department of Energy Contract No. DE-AC02-98CH1-886, and with support of RIKEN(Japan) and Renaissance Technologies Corp.(USA)

The Relativistic Heavy Ion Collider~(RHIC) as the first high energy polarized proton collider was designed to provide polarized proton collisions at a maximum beam energy of 250GeV. It has been providing collisions at a beam energy of 100GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during the acceleration from injection to 100GeV with careful control of the betatron tunes and the vertical orbit distortions. However, the intrinsic spin resonances beyond 100GeV are about a factor of two stronger than those below 100GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were accelerated to the record energy of 250GeV in RHIC with a polarization of 45\% measured at top energy in 2006. The polarization measurement as a function of beam energy also shows some polarization loss around 136GeV, the first strong intrinsic resonance above 100GeV. This paper presents the results and discusses the sensitivity of the polarization survival to orbit distortions.

slides icon Slides  
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.

THPAS105 Stern-Gerlach Force on a Precessing Magnetic Moment 3729
  • M. Conte
    INFN Genova, Genova
  • A. U. Luccio, W. W. MacKay
    BNL, Upton, Long Island, New York
  • M. Pusterla
    Univ. degli Studi di Padova, Padova
  The use of the Stern-Gerlach interaction for attaining the spin-states separation of an (anti)proton beam circulating in a ring is reconsidered in a new method where the particle magnetic moments are made to precess while they are undergoing energy exchanges, either positive or negative, with the e.m. fields of an array of radio frequency resonators tuned in the Transverse Electric mode. This proposal represents an improvement with respect to cases considered in the past when the magnetic moments were conserving their directions in space.