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Ahrens, L.

Paper Title Page
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.  
MOPLT170 eRHIC, Future Electron-ion Collider at BNL 923
 
  • V. Ptitsyn, L. Ahrens, M. Bai, J. Beebe-Wang, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, R. Calaga, X. Chang, E.D. Courant, A. Deshpande, A.V. Fedotov, W. Fischer, H. Hahn, J. Kewisch, V. Litvinenko, W.W. MacKay, C. Montag, S. Ozaki, B. Parker, S. Peggs, T. Roser, A. Ruggiero, B. Surrow, S. Tepikian, D. Trbojevic, V. Yakimenko, S.Y. Zhang
    BNL, Upton, Long Island, New York
  • D.P. Barber
    DESY, Hamburg
  • M. Farkhondeh, W. Franklin, W. Graves, R. Milner, C. Tschalaer, J. Van der Laan, D. Wang, F. Wang, A. Zolfaghari, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • A.V. Otboev, Y.M. Shatunov
    BINP SB RAS, Novosibirsk
 
  The paper reviews the progress made lately in the design of eRHIC, proposed future electron-ion collider on the basis of the existing RHIC machine. The eRHIC aims to provide collisions of electrons and positrons on ions and protons in center mass energy range of 25-70 GeV. The goal luminosities are in 1032-1033 1/(s*cm2) values for e-p and in 1030-1031 1/(s*cm2) values for e-Au collisions. An essential design requirement is to provide longitudinally polarized beams of electrons and protons (and, possibly lighter ions) at the collision point. The eRHIC ZDR has been recently developed which considers various aspects of the accelerator design. An electron accelerator, which delivers about 0.5A polarized electron beam current in the electron energy range of 5 to 10 GeV, should be constructed at the BNL near existing ion rings of the RHIC collider and should intersect an ion ring at least in one of the available ion ring interaction regions. In order to reach the luminosity goals some upgrades in ion rings also would be required. Ways to reach lower beam emmittances (electron cooling) and higher beam intensities have to be realized.  
MOPLT175 A Method to Measure the Focusing Properties (R_Matrix) of a Magnet 935
 
  • N. Tsoupas, L. Ahrens, K.A. Brown, D. Gassner, J. Glenn, Y.Y. Lee, T. Roser, P. Thieberger, J. Wei
    BNL, Upton, Long Island, New York
 
  We discuss a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to non-conventional magnets that deviate from the usual dipole magnets or other multipole magnets which are commonly used in a synchrotron. In this category of non-conventional magnets, fall special magnets, which come under the name Snakes. Such magnets are being used in synchrotron accelerators[*,**] to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances. This method of measuring the focusing properties of a magnet requires the use of low energy and high rigidity heavy-ions which may be obtained from the BNL Tandem accelerator.In brief the method consists on, injecting low emittance beamlets of lightly stripped heavy ions into a magnet and measuring the coordinates, of these narrowbeamlets, at the entrance and exit of the magnet.From the measurement of these coordinates of the narrowbeamlets we can deduce information on the R matrix and higher order matrix elements that define the focusing properties of the magnet.

* T. Roser, AIP Conf. Proc. 187 (1988) 1221** H.Huang, et. al. Phys. Rev. Lett. 73 (1994) 2982

 
TUPLT179 Mini-bunched and Micro-bunched Slow Extracted Beams from the AGS 1544
 
  • K.A. Brown, L. Ahrens, J.M. Brennan, J. Glenn, M. Sivertz, N. Tsoupas
    BNL, Upton, Long Island, New York
  • S.R. Koscielniak
    TRIUMF, Vancouver
 
  BNL's AGS has a long history of providing slow extracted proton beams to fixed target experiments. This program of providing high quality high intensity beams continues with two new experiments currently being designed for operation at the AGS; both of these new experiments require slow extracted beam, but with an added requirement of those beams experiments require slow extracted beam, but with an added requirement of those beams experiments and initial tests have been performed. In this report we will describe the beam requirements for the two experiments, and present results of detailed simulations and initial beam tests.  
TUPLT180 Results of the NASA Space Radiation Laboratory Beam Studies Program at BNL 1547
 
  • K.A. Brown, L. Ahrens, R.H. Beuttenmuller, I.-H. Chiang, D.C. Elliott, D. Gassner, Z. Li, I. Marneris, J. Mead, J. Morris, D. Phillips, V. Radeka, A. Rusek, N. Tsoupas, B. Yu, K. Zeno
    BNL, Upton, Long Island, New York
 
  The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. The purpose of the NSRL beam studies program is to develop a clear understanding of the beams delivered to the facility, to fully characterize those beams, and to develop new capabilities in the interest of understanding the radiation environment in space. In this report we will describe the first results from this program.  
TUPLT181 Results of the First Run of the NASA Space Radiation Laboratory at BNL 1550
 
  • K.A. Brown, L. Ahrens, J.M. Brennan, J. DeLong, C. Gardner, D. Gassner, J. Glenn, Y. Kotlyar, I. Marneris, A. Rusek, N. Tsoupas, K. Zeno
    BNL, Upton, Long Island, New York
 
  The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The results of commissioning of this new facility were reported in [*]. In this report we will describe the results of the first run. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. Many modes of operation were explored during the first run, demonstrating all the capabilities designed into the system. Heavy ion intensities from 100 particles per pulse up to 2×109 particles per pulse were delivered to a large variety of experiments, providing a dose range up to 70 G/min over a 5x5 cm2 area. Results presented will include those related to the production of beams that are highly uniform in both the transverse and longitudinal planes of motion [**].

* K.A.Brown, et al, ‘‘Commissioning Results of Slow Extraction of Heavy Ions from the AGS Booster‘‘, Proceedings of the 2003 Particle Accelerator Conference, Portland, OR, 2003** N.Tsoupas, et al, ‘‘Commissioning of the Beam Transfer Line of the Booster Application Facility (BAF) at BNL'', These Proceedings

 
TUPLT190 Acceleration of Polarized Beams using Multiple Strong Partial Siberian Snakes 1577
 
  • T. Roser, L. Ahrens, M. Bai, E.D. Courant, J. Glenn, R.C. Gupta, H. Huang, A.U. Luccio, W.W. MacKay, N. Tsoupas, E. Willen
    BNL, Upton, Long Island, New York
  • M. Okamura, J. Takano
    RIKEN, Saitama
 
  Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.