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Van Zeijts, J.

Paper Title Page
TUPLT012 Adjusting the IP Beta-functions in RHIC. 1156
 
  • W. Wittmer, F. Zimmermann
    CERN, Geneva
  • F.C. Pilat, V. Ptitsyn, J. Van Zeijts
    BNL, Upton, Long Island, New York
  
  The beta- functions at the IP can be adjusted without perturbation of other optics functions via several approaches. In this paper we describe a scheme based on a vector knob, which assigns fixed values to the different tuning quadrupoles and scales them by a common multiplier. The values for the knob vector were calculated for a lattice without any errors using MADX. Previous studies for the LHC have shown that this approach can meet the design goals. A specific feature of the RHIC lattice is the nested power supply system. To cope with the resulting problems a detailed response matrix analysis has been carried out and different sets of knobs were calculated and compared. The knobs are tested at RHIC during the 2004 run and preliminary results maybe discussed. Simultaneously a new approach to measure the beam sizes of both colliding beams at the IP, based on the tune ability provided by the knobs, was developed and tested.  
TUPLT191 Transverse Optics Improvements for RHIC Run 4 1580
 
  • J. Van Zeijts
    BNL, Upton, Long Island, New York
  
  The magnetic settings in RHIC are driven by an online model, and the quality of the resulting lattice functions depend on the correctness of the settings, including knowledge of the magnet transfer-functions. Here we first present the different inputs into the online model, including dipole sextupole compenents, used to set tunes and chromaticities along the ramp. Next, based on an analysis of measured tunes and chromaticities along the fy03 polarized proton ramp, we present predictions for quadrupole transfer-function changes. The changes are implemented for the fy04 Au ramp, and we show the improved model agreement for tunes, and chromaticities along the ramp, and measured transverse phase-advance at store. We also describe model improvements for derived observables like the quality of transverse bump closure and observed luminosity ratios between individual interaction points.  
THPLT184 An Online Longitudinal Vertex and Bunch Spectrum Monitor for RHIC 2879
 
  • J. Van Zeijts, R. Lee
    BNL, Upton, Long Island, New York
  
  The longitudinal bunch profile acquisition system at RHIC was recently upgraded to allow online measurements of the bunch spectrum, and collision vertex location and shape. The system allows monitoring the evolution of these properties along the ramp, at transition and rebucketing, and at store conditions. We describe some of the hardware and software changes, and show an application of the system in optimizing the cogging of the colliding beams.  
MOPLT165 Luminosity Increases in Gold-gold Operation in RHIC 917
 
  • W. Fischer, L. Ahrens, J. Alessi, M. Bai, D. Barton, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, D. Bruno, J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K.A. Drees, W. Fu, G. Ganetis, J. Glenn, T. Hayes, P. He, H.-C. Hseuh, H. Huang, P. Ingrassia, U. Iriso, R. Lee, Y. Luo, W.W. MacKay, G. Marr, A. Marusic, R. Michnoff, C. Montag, J. Morris, T. Nicoletti, B. Oerter, C. Pearson, S. Peggs, A. Pendzick, F.C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, A. Sidi-Yekhlef, L. Smart, S. Tepikian, R. Tomas, D. Trbojevic, N. Tsoupas, J. Tuozzolo, J. Van Zeijts, K. Vetter, K. Yip, A. Zaltsman, S.Y. Zhang, W. Zhang
    BNL, Upton, Long Island, New York
  
  After an exploratory phase, during which a number of beam parameters were varied, the RHIC experiments now demand high luminosity to study heavy ion collisions in detail. Presently RHIC operates routinely above its design luminosity. In the first 4 weeks of its current operating period (Run-4) the machine has delivered more integrated luminosity that during the 14 weeks of the last gold-gold operating period (Run-2). We give an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency.  
MOPLT167 RHIC Operation with Longitudinally Polarized Protons 920
 
  • H. Huang, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, A.U. Luccio, W.W. MacKay, C. Montag, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, S. Tepikian, D. Trbojevic, J. Van Zeijts, A.Y. Zelinsky, S.Y. Zhang
    BNL, Upton, Long Island, New York
  
  Longitudinally polarized proton beams have been accelerated, stored and collided at 100GeV in the Relativistic Heavy Ion Collider (RHIC) to study spin effects in the hadronic reactions. The essential equipment includes four Siberian snakes, eight spin rotators and a fast relative polarimeters in each of the two RHIC rings as well as local polarimeters at the STAR and PHENIX detectors. This paper summarizes the performance of RHIC as a polarized proton collider.  
MOPLT178 RHIC Pressure Rise 944
 
  • S.Y. Zhang, J. Alessi, M. Bai, M. Blaskiewicz, P. Cameron, K.A. Drees, W. Fischer, R.P. Fliller III, D. Gassner, J. Gullotta, P. He, H.-C. Hseuh, H. Huang, U. Iriso, R. Lee, Y. Luo, W.W. MacKay, C. Montag, B. Oerter, S. Peggs, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, L. Smart, P. Thieberger, D. Trbojevic, J. Van Zeijts, L. Wang, J. Wei, K. Zeno
    BNL, Upton, Long Island, New York
  
  Beam induced pressure rise remains an intensity limit at the RHIC for both heavy ion and polarized proton operations. The beam injection pressure rise at warm sections has been diagnosed due to electron cloud effect. In addition, pressure rise of heavy ion operation at the beam transition has caused experiment background problem in deuteron-gold run, and it is expected to take place in gold-gold run at high intensities. This type of pressure rise is related to beam momentum spread, and the electron cloud seems not dominant. Extensive approaches for both diagnosis and looking-for-remedies are undergoing in the current gold operation, RUN 4. Results of beam scrubbing, NEG pipe in RHIC ring, beam scraping test of ion desorption, beam momentum effect at the transition, beam gap effect, solenoid effect, and NEG pipe ion desorption test stand will be presented.