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BEAM-BEAM 2003 SUMMARY.

Description: This paper summarizes the presentations and discussions of the Beam-Beam'03 workshop, held in Montauk, Long Island, from May 19 to 23, 2003. Presentations and discussions focused on halo generation from beam-beam interactions; beam-beam limits, especially coherent limits and their effects on existing and future hadron colliders; beam-beam compensation techniques, particularly for long-range interactions; and beam-beam study tools in theory, simulation, and experiment.
Date: May 19, 2003
Creator: FISCHER,W. SEN,T.
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Partner: UNT Libraries Government Documents Department
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LUMINOSITY INCREASE AT THE INCOHERENT BEAM BEAM LIMIT WITH SIX SUPERBUNCHES IN RHIC.

Description: By colliding bunches of greater length under a larger angle, the tune spread caused by the beam-beam interaction can be reduced. Assuming a constant limit for the beam-beam tune shift, the bunch intensity can then be raised. In this way, a luminosity increase is possible. We review this strategy for proton beams in RHIC, with two collisions and consider six long bunches. Barrier cavities are used to fill every accelerating bucket of the machine, except for an abort gap, and to create the superb… more
Date: May 19, 2003
Creator: FISCHER,W. BLASKIEWICZ,M.
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Partner: UNT Libraries Government Documents Department
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BUNCH PATTERNS AND PRESSURE RISE IN RHIC.

Description: The RHIC luminosity is limited by pressure rises with high intensity beams. At injection and store, the dominating cause for the pressure rise was shown to be electron clouds. We discuss bunch distributions along the circumference that minimize the electron cloud effect in RHIC. Simulation results are compared with operational observations.
Date: July 5, 2004
Creator: FISCHER,W. IRISO-ARIZ,U.
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Partner: UNT Libraries Government Documents Department
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MEASUREMENT OF MULTIPOLE STRENGTHS FROM RHIC BPM DATA.

Description: Recently resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of BPM data. Based on these measurements a new analysis has been derived to extract multipole strengths. In this paper we present experimental measurements of sextupolar and skew quadrupolar strengths carried out at RHIC. A non-destructive measurement using an AC dipole is also presented.
Date: July 5, 2004
Creator: TOMAS,R. BAI,M. FISCHER,W. ET AL.
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Partner: UNT Libraries Government Documents Department
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TUNE MODULATION FROM BEAM BEAM INTERACTION AND UNEQUAL RADIO FREQUENCIES IN RHIC.

Description: The two RHIC rings have independent rf systems to accommodate different species. Thus, the radio frequencies can differ when the phase and radial loops are closed, and the if frequencies of the two rings are not synchronized. A radio frequency difference leads to longitudinally moving beam crossing points. When the crossing points are between the beam splitting dipoles, the beams experience the beam-beam interaction. Outside the interaction region the beam-beam interaction is switched off. In t… more
Date: May 19, 2003
Creator: FISCHER,W. CAMERON,P. PEGGS,S. SATOGATA,T.
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Partner: UNT Libraries Government Documents Department
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LUMINOSITY INCREASES IN GOLD-GOLD OPERATION IN RHIC.

Description: After an exploratory phase, during which a number of beam parameters were varied, the RHIC experiments now demand higher luminosity to study heavy ion collisions in detail. In gold-gold, operation, RHIC delivers now twice the design luminosity. During the last gold-gold operating period (Run-4) the machine delivered 15 times more luminosity than during the previous gold-gold operating period (Run-2), two years ago. We give an overview of the changes that increased the instantaneous luminosity a… more
Date: July 5, 2004
Creator: FISCHER,W. AHERNS,L. BAI,M. ET AL.
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Partner: UNT Libraries Government Documents Department
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BEAM SCRUBBING FOR RHIC POLARIZED PROTON RUN.

Description: One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. A beam scrubbing study shows that with a reasonable period of time of running high intensity 112-bunch proton beam, the pressure rise can be reduced, allowing higher beam intensity.
Date: July 5, 2004
Creator: ZHANG,S. Y. FISCHER,W. HUANG,H. ROSER,T.
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Partner: UNT Libraries Government Documents Department
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UP-GRADED RHIC INJECTION SYSTEM.

Description: The design of the RHIC injection systems anticipated the possibility of filling and operating the rings with a 120 bunch pattern, corresponding to 110 bunches after allowing for the abort gap. Beam measurements during the 2002 run confirmed the possibility, although at the expense of severe transverse emittance growth and thus not on an operational basis. An improvement program was initiated with the goal of reducing the kicker rise time from 110 to {approx}95 ns and of minimizing pulse timing … more
Date: May 12, 2003
Creator: HAHN,H. FISCHER,W. SEMERTZIDIS,Y. K. WARBURTON,D. S.
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Partner: UNT Libraries Government Documents Department
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QUEST FOR A NEW WORKING POINT IN RHIC.

Description: The beam-beam interaction is a limiting factor in RHIC's performance, particularly in proton operation. Changing the working point is a strategy to alleviate the beam-beam effect and improve the performance of the machine. Experiments at injection energy and simulations have been performed for a set of working points to determine the best candidates.
Date: July 5, 2004
Creator: TOMAS,R. BAI,M. FISCHER,W. PTITSYN,V. SATOGATA,T. ROSER,T.
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Partner: UNT Libraries Government Documents Department
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ELECTRON CLOUD AND PRESSURE RISE SIMULATIONS FOR RHIC.

Description: Beam induced electron multipacting may be among the main reasons for the vacuum pressure rise when circulating high intensity ion and proton beams in RHIC. Latest simulation results are benchmarked with recent experimental observations for RHIC, and compared to other general computer codes. The influence of the electron multipacting to the vacuum properties is also discussed.
Date: May 12, 2003
Creator: IRISO-ARIZ,U. BLASKIEWICZ,M. DREES,A. FISCHER,W. PEGGS,S. TRBOJEVIC,D.
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Partner: UNT Libraries Government Documents Department
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RF TECHNIQUES FOR IMPROVED LUMINOSITY IN RHIC.

Description: The luminosity of the Relativistic Heavy Ion Collider has improved significantly [1] over the first three physics runs. A number of special rf techniques have been developed to facilitate higher luminosity. The techniques described herein include: an ultra low-noise rf source for the 197 MHz storage rf system, a frequency shift switch-on technique for transferring bunches from the acceleration to the storage system, synchronizing the rings during the energy ramp (including crossing the transiti… more
Date: July 5, 2004
Creator: BRENNAN,J. M. BLASKIEWICZ,J. BUTLER,J. DELONG,J. FISCHER,W. HAYES,T.
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Partner: UNT Libraries Government Documents Department
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LONGITUDINAL SOLUTIONS IN RHIC.

Description: Stable, coherent, longitudinal oscillations have been observed in the RHIC accelerator. Within the context of perturbation theory, the beam parameters and machine impedance suggest these oscillations should be Landau damped. When nonlinear effects are included, long lived, stable oscillations become possible for low intensity beams. Simulations and theory are compared with data.
Date: May 12, 2003
Creator: BLASKIEWICZ,M. BRENNAN,J. M. FISCHER,W. CAMERON,P. WEI,J. LUQUE,A. SCHAMEL,H.
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Partner: UNT Libraries Government Documents Department
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HIGH LUMINOSITY RHIC INSERTIONS, 0.5M BETA AT IP.

Description: An increase in RHIC collision luminosity is possible by reducing the beam size at the interaction point (IP). They present a method for reducing the IP beta function, {beta}*, from the design minimum of 1m to 0.5m. They demonstrate that this {beta}* = 0.5m configuration is achievable with existing RHIC power supplies for 100 GeV protons. They discuss the correction of the higher order IR multi-poles and the second order chromaticity.
Date: May 12, 2003
Creator: TEPIKIAN,S. FISCHER,W. MACKAY,W. PILAT,F. HUANG,H. PTITSYN,V. SATOGATA,T. TRBOJEVIC,D. VAN ZEIJTS,J.
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Partner: UNT Libraries Government Documents Department
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Performance Limitations in High-Energy Ion Colliders

Description: High-energy ion colliders (hadron colliders operating with ions other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams limits are set by space charge, charge exchange,… more
Date: May 16, 2005
Creator: Fischer, W.
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Partner: UNT Libraries Government Documents Department
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Storage Rings

Description: Storage rings are circular machines that store particle beams at a constant energy. Beams are stored in rings without acceleration for a number of reasons (Tab. 1). Storage rings are used in high-energy, nuclear, atomic, and molecular physics, as well as for experiments in chemistry, material and life sciences. Parameters for storage rings such as particle species, energy, beam intensity, beam size, and store time vary widely depending on the application. The beam must be injected into a storag… more
Date: January 1, 2011
Creator: Fischer, W.
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
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RHIC PROTON BEAM LIFETIME INCREASE WITH 10- AND 12-POLE CORRECTORS

Description: The RHIC beam lifetime in polarized proton operation is dominated by the beam-beam effect, parameter modulations, and nonlinear magnet errors in the interaction region magnets. Sextupole and skew sextupole errors have been corrected deterministically for a number of years based on tune shift measurements with orbit bumps in the triplets. During the most recent polarized proton run 10- and 12- pole correctors were set through an iterative procedure, and used for the first time operationally in o… more
Date: May 23, 2010
Creator: Fischer, W.
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Partner: UNT Libraries Government Documents Department
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RHIC LUMINOSITY UPGRADE PROGRAM

Description: The Relativistic Heavy Ion Collider (RHIC) operates with either ions or polarized protons. After increasing the heavy ion luminosity by two orders of magnitude since its commissioning in 2000, the current luminosity upgrade program aims for an increase by another factor of 4 by means of 3D stochastic cooling and a new 56 MHz SRF system. An Electron Beam Ion Source is being commissioned that will allow the use of uranium beams. Electron cooling is considered for collider operation below the curr… more
Date: May 23, 2010
Creator: Fischer, W.
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Partner: UNT Libraries Government Documents Department
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Rhic Performance and Future Plans

Description: The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, consisting of two 3.8 km long superconducting rings, was commissioned in 1999. Since then the machine collided fully stripped gold ions at five different energies, up to 100 GeV/u, deuterons with gold ions at 100 GeV/u, and protons at 100 GeV with a beam polarizations of up 45%. Over four operating periods the heavy ion luminosity has increased by two orders of magnitude, and now exceeds the design value by a factor o… more
Date: October 10, 2004
Creator: Fischer, W.
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Partner: UNT Libraries Government Documents Department
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Nonlinear dynamics experiments

Description: The goal of nonlinear dynamics experiments is to improve the understanding of single particle effects that increase the particle amplitude and lead to loss. Particle motion in storage rings is nearly conservative and for transverse dynamics the Hamiltonian in action angle variables (I{sub x},I{sub y},{phi}{sub x},{phi}{sub y}) near an isolated resonance k{nu}{sub x} + l{nu}{sub y} {approx} p is H = I{sub x}{nu}{sub x0} + I{sub y}{nu}{sub y0} + g(I{sub x}, I{sub y}) + h(I{sub x}, I{sub y})cos(k{… more
Date: January 1, 2011
Creator: Fischer, W.
Item Type: Refine your search to only Book
Partner: UNT Libraries Government Documents Department
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Summary of Beam Beam Observations During Stores in Rhic.

Description: During stores, the beam-beam interaction has a significant impact on the beam and luminosity lifetimes in RHIC. This was observed in heavy ion, and even more pronounced in proton collisions. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. In addition, RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. Co… more
Date: May 19, 2003
Creator: Fischer, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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