• M. Blaskiewicz, J. M. Brennan, F. Severino
  BNL, Upton, Long Island, New York

Stochastic cooling of 100 GeV/nucleon bunched beams has been achieved in the Relativistic Heavy Ion Collider (RHIC). The physics and technology of the longitudinal cooling system are discussed, and plans for a transverse cooling system are outlined.

• K. A. Drees, L. Ahrens, J. G. Alessi, M. Bai, D. S. Barton, J. Beebe-Wang, M. Blaskiewicz, J. M. Brennan, K. A. Brown, D. Bruno, J. J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, W. Fischer, W. Fu, G. Ganetis, J. W. Glenn, M. Harvey, T. Hayes, H.-C. Hseuh, H. Huang, J. Kewisch, R. C. Lee, V. Litvinenko, Y. Luo, W. W. MacKay, G. J. Marr, A. Marusic, R. J. Michnoff, C. Montag, J. Morris, B. Oerter, F. C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, F. Severino, K. Smith, S. Tepikian, D. Trbojevic, N. Tsoupas, J. E. Tuozzolo, A. Zaltsman, S. Y. Zhang
  BNL, Upton, Long Island, New York

After the last successful RHIC Au-Au run in 2004 (Run-4), RHIC experiments now require significantly enhanced luminosity to study very rare events in heavy ion collisions. RHIC has demonstrated its capability to operate routinely above its design average luminosity per store of 2x10²⁶ cm^-2 s^-1. In Run-4 we already achieved 2.5 times the design luminosity in RHIC. This luminosity was achieved with only 40% of bunches filled, and with β* = 1 m. However, the goal is to reach 4 times the design luminosity, 8x10²⁶ cm^-2 s^-1, by reducing the beta* value and increasing the number of bunches to the accelerator maximum of 111. In addition, the average time in store should be increased by a factor of 1.1 to about 60% of calendar time. We present an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency of RHIC Au-Au operations during Run-7.

• C. J. Gardner, L. Ahrens, J. G. Alessi, J. Benjamin, M. Blaskiewicz, J. M. Brennan, K. A. Brown, C. Carlson, W. Fischer, J. W. Glenn, M. Harvey, T. Hayes, H. Huang, G. J. Marr, J. Morris, F. C. Pilat, T. Roser, F. Severino, K. Smith, D. Steski, P. Thieberger, N. Tsoupas, A. Zaltsman, K. Zeno
  BNL, Upton, Long Island, New York

Gold ions for the 2007 run of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of this chain of accelerators will be reviewed with a focus on improvements in the quality of beam delivered to RHIC. In particular, more uniform stripping foils between Booster and AGS, and a new bunch merging scheme in AGS promise to provide beam bunches with reduced longitudinal emittance for RHIC.

• T. Satogata, L. Ahrens, M. Bai, J. M. Brennan, D. Bruno, J. J. Butler, K. A. Drees, A. V. Fedotov, W. Fischer, M. Harvey, T. Hayes, W. Jappe, R. C. Lee, W. W. MacKay, G. J. Marr, R. J. Michnoff, B. Oerter, E. Pozdeyev, T. Roser, F. Severino, K. Smith, S. Tepikian, N. Tsoupas
  BNL, Upton, Long Island, New York

There is significant interest in RHIC heavy ion collisions at c.m. energies of 5-50 GeV/u, motivated by a search for the QCD phase transition critical point. The low end of this energy range is well below the nominal RHIC injection c.m. energy of 19.6 GeV/u. There are several challenges that face RHIC operations in this regime, including longitudinal acceptance, magnet field quality, lattice control, and luminosity monitoring. We report on the status of work to address these challenges and include results from beam tests of low-energy RHIC operations with protons and gold.