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Drees, K.A.

Paper Title Page
MOPA007 Polarized Proton Collisions at RHIC 600
 
  • M. Bai, L. Ahrens, J.G. Alessi, J. Beebe-Wang, M. Blaskiewicz, A. Bravar, J.M. Brennan, 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. Glenn, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, U. Iriso, 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, T. Nicoletti, P. Oddo, B. Oerter, O. Osamu, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, K. Smith, S. Tepikian, R. Tomas, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, K. Vetter, M. Wilinski, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
    BNL, Upton, Long Island, New York
  • I.G. Alekseev, D. Svirida
    ITEP, Moscow
  
  Funding: The work was performed under the auspices of the U.S. Department of Energy and RIKEN Japan.

The Relativistic Heavy Ion Collider~(RHIC) provides not only collisions of ions but also collisions of polarized protons. In a circular accelerator, the polarization of polarized proton beam can be partially or fully lost when a spin depolarizing resonance is encountered. To preserve the beam polarization during acceleration, two full Siberian snakes were employed in RHIC to avoid depolarizing resonances. In 2003, polarized proton beams were accelerated to 100~GeV and collided in RHIC. Beams were brought into collisions with longitudinal polarization at the experiments STAR and PHENIX by using spin rotators. RHIC polarized proton run experience demonstrates that optimizing polarization transmission efficiency and improving luminosity performance are significant challenges. Currently, the luminosity lifetime in RHIC is limited by the beam-beam effect. The current state of RHIC polarized proton program, including its dedicated physics run in 2005 and efforts to optimize luminosity production in beam-beam limited conditions are reported.

 
TPAT095 Beam Induced Pressure Rise at RHIC 4308
 
  • S.Y. Zhang, J.G. Alessi, M. Bai, M. Blaskiewicz, P. Cameron, K.A. Drees, W. Fischer, J. Gullotta, P. He, H.-C. Hseuh, H. Huang, U. Iriso, R.C. Lee, V. Litvinenko, W.W. MacKay, T. Nicoletti, B. Oerter, S. Peggs, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, L. Smart, L. Snydstrup, P. Thieberger, D. Trbojevic, L. Wang, J. Wei, K. Zeno
    BNL, Upton, Long Island, New York
  
  Beam induced pressure rise in RHIC warm sections is currently one of the machine intensity and luminosity limits. This pressure rise is mainly due to electron cloud effects. The RHIC warm section electron cloud is associated with longer bunch spacings compared with other machines, and is distributed non-uniformly around the ring. In addition to the countermeasures for normal electron cloud, such as the NEG coated pipe, solenoids, beam scrubbing, bunch gaps, and larger bunch spacing, other studies and beam tests toward the understanding and counteracting RHIC warm electron cloud are of interest. These include the ion desorption studies and the test of anti-grazing ridges. For high bunch intensities and the shortest bunch spacings, pressure rises at certain locations in the cryogenic region have been observed during the past two runs. Beam studies are planned for the current 2005 run and the results will be reported.

Work performed under the auspices of the US Department of Energy.

 
TPAT093 Operations and Performance of RHIC as a Cu-Cu Collider 4281
 
  • F.C. Pilat, L. Ahrens, M. Bai, D.S. Barton, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, D. Bruno, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K.A. Drees, W. Fischer, G. Ganetis, C.J. Gardner, J. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, P. Ingrassia, U. Iriso, R.C. Lee, V. Litvinenko, Y. Luo, W.W. MacKay, G.J. Marr, A. Marusic, R.J. Michnoff, C. Montag, J. Morris, T. Nicoletti, B. Oerter, V. Ptitsyn, T. Roser, T. Russo, J. Sandberg, T. Satogata, C. Schultheiss, S. Tepikian, R. Tomas, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, K. Vetter, A. Zaltsman, K. Zeno, S.Y. Zhang, W. Zhang
    BNL, Upton, Long Island, New York
  
  Funding: Work performed under the auspices of the U.S. Department of Energy.

The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.