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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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

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.
Partner: UNT Libraries Government Documents Department
open access

Summary of the ecl2 Workshop

Description: We summarize the ECL2 workshop on electron cloud clearing, which was held at CERN in early March 2007, and highlight a number of novel ideas for electron cloud suppression, such as continuous clearing electrodes based on enamel, slotted structures, and electrete inserts.
Date: April 9, 2007
Creator: Fischer, W.
Partner: UNT Libraries Government Documents Department
open access

Transverse Echo Measurements in Rhic.

Description: Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular they examine the echo… more
Date: September 18, 2005
Creator: Fischer, W.
Partner: UNT Libraries Government Documents Department
open access

Rhic Operational Status and Upgrade Plans.

Description: Since 2000 RHIC has collided, at 8 energies, 4 combinations of ion species, ranging from gold ions to polarized protons, and including the collisions of deuterons with gold ions. During that time the heavy ion and polarized proton peak luminosities increased by two orders and one order of magnitude respectively. The average proton polarization in store reached 65%. Planned upgrades include the evolution to the Enhanced Design parameters by about 2008, the construction of an Electron Beam Ion So… more
Date: June 23, 2006
Creator: Fischer, W.
Partner: UNT Libraries Government Documents Department
open access

Evaluation, design, development and delivery of a 1200-kV prototype termination. Ninth technical progress report, December 1, 1980-February 28, 1981

Description: Tests are continuing on the shatter-resistant weathercase models and small samples. Two epoxy weathercase material samples are still undergoing accelerated tensile creep tests. Progress is reported on the design of the full scale prototype termination.
Date: April 30, 1981
Creator: Billings, J S & Fischer, W H
Partner: UNT Libraries Government Documents Department
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Optimization of the Phase Advance Between Rhic Interaction Points.

Description: The authors consider a scenario of having two identical Interaction Points (IPs) in the Relativistic Heavy Ion Collider (RHIC). The strengths of beam-beam resonances strongly depend on the phase advance between these two IPs and therefore certain phase advances could improve beam life-time and luminosity. The authors compute the dynamic aperture (DA) as function of the phase advance between these IPs to find the optimum settings.The beam-beam interaction is treated in the weak-strong approximat… more
Date: May 16, 2005
Creator: Tomas, R. & Fischer, W.
Partner: UNT Libraries Government Documents Department
open access

Computational challenges for beam-beam simulation for RHIC

Description: In this article we will review the computational challenges in the beam-beam simulation for the polarized proton run of the Relativistic Heavy Ion Collider (RHIC). The difficulties in our multi-particle and million turn tracking to calculate the proton beam lifetime and proton beam emittance growth due to head-on beam-beam interaction and head-on beam-beam compensation are presented and discussed. Solutions to obtain meaningful physics results from these trackings are proposed and tested. In th… more
Date: October 1, 2010
Creator: Luo, Y. & Fischer, W.
Partner: UNT Libraries Government Documents Department
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