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Malitsky, N.

Paper Title Page
TUPMS074 Collective Effects in the NSLS-II Storage Ring 1344
 
  • S. Krinsky, J. Bengtsson, J. S. Berg, M. Blaskiewicz, A. Blednykh, W. Guo, N. Malitsky, C. Montag, B. Podobedov, J. Rose, N. A. Towne, L.-H. Yu
    BNL, Upton, Long Island, New York
  • F. Wang
    MIT, Middleton, Massachusetts
  
  Funding: This work was supported by Department of Energy contract DE-AC02-98CH10886.

A new high-brightness synchrotron light source (NSLS-II) is under design at BNL. The 3-GeV NSLS-II storage ring has a double-bend achromatic lattice with damping wigglers installed in zero-dispersion straights to reduce the emittance below 1nm. In this note, we present an overview of the impact of collective effects upon the performance of the storage ring. Subjects discussed include Touschek lifetime, intra-beam scattering, instability thresholds due to ring impedance, and use of a third-harmonic Landau cavity.

 
TUPAS099 A Near-Integer Working Point for Polarized Protons in the Relativistic Heavy Ion Collider 1871
 
  • C. Montag, M. Bai, J. Beebe-Wang, M. Blaskiewicz, R. Calaga, W. Fischer, A. K. Jain, Y. Luo, N. Malitsky, T. Roser, S. Tepikian
    BNL, Upton, Long Island, New York
  
  Funding: Work performed under the auspices of the US Department of Energy.

To achieve the RHIC polarized proton enhanced luminosity goal of 150*1030 cm-2 sec-1 on average in stores at 250 GeV, the luminosity needs to be increased by a factor of 3 compared to what was achieved in 2006. Since the number of bunches is already at its maximum of 111, limited by the injection kickers and the experiments' time resolution, the luminosity can only be increased by either increasing the bunch intensity and/or reducing the beam emittance. This leads to a larger beam-beam tuneshift parameter. Operation during 2006 has shown that the beam-beam interaction is already dominating the luminosity lifetime. To overcome this limitation, a near-integer working point is under study. We will present recent results of these studies.

 
FRPMS109 Measurement and Correction of Third Resonance Driving Term in the RHIC 4351
 
  • Y. Luo, M. Bai, J. Bengtsson, R. Calaga, W. Fischer, N. Malitsky, F. C. Pilat, T. Satogata
    BNL, Upton, Long Island, New York
  
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH10886.

To further improve the polarized proton (pp) run collision luminosity in the Relativistic Heavy Ion Collider, correction of the horizontal two-third resonance is desirable to increase the available tune space. The third resonance driving term (RTD) is measured with the turn-by-turn (TBT) beam position monitor (BPM) data with AC dipole excitation. A first order RTD response matrix based on the optics model is used to on-line compensate the third resonance driving term h30000 while keeping other first order RTDs and first order chromaticities unchanged. The results of beam experiment and simulation correction are presented and discussed.

 
FRPMS110 Online Nonlinear Chromaticity Correction Using Off-Momentum Tune Response Matrix 4357
 
  • Y. Luo, W. Fischer, N. Malitsky, S. Tepikian, D. Trbojevic
    BNL, Upton, Long Island, New York
  
  Funding: Work supported by U. S. DOE under contract No DE-AC02-98CH10886.

With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be corrected on-line by matching the off-momentum tunes onto the wanted off-momentum tunes with linear chromaticity only. The Newton method with singular value decomposition (SVD) technique is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted to simplify and fasten the on-line optimization process. The off-momentum tune response matrix can be calculated with the on-line accelerator optics model or directly measured with the real beam. This correction method will be verified and used in the coming RHIC run'07.