| Paper | Title | Page |
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| MOPC057 | R&D Energy Recovery Linac at Brookhaven National Laboratory | 193 |
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| Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R&D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel Zigzag-type merger. We present the performance of the R&D ERL elements and detailed commissioning plan. | ||
| WEPP015 | Experience with IBS-suppression Lattice in RHIC | 2557 |
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| An intra-beam scattering (IBS) is the limiting factor of the luminosity lifetime for RHIC operating with heavy ions. In order to suppress the IBS we designed and implemented new lattice with higher betatron tunes. This lattice had been developed during last three years and had been used for gold ions in yellow ring of the RHIC during d-Au part of the RHIC Run-8. The use of this lattice allowed both significant increases in the luminosity lifetime and the luminosity levels via reduction of beta-stars in the IPs. In this paper we report on the development, the tests and the performance of IBS-suppression lattice in RHIC, including the resulting increases in the peak and the average luminosity. We also report on our plans for future steps with the IBS suppression. | ||
| WEPP016 | FEL-based Coherent Electron Cooling for High-energy Hadron Colliders | 2560 |
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Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation of such beams is too feeble and two common methods, stochastic and electron cooling, are not efficient in providing significant cooling for high energy hadron, especially proton, colliders. In this paper we discuss a practical scheme of Coherent Electron Cooling, which promises short cooling times (below one hour) for intense proton beams in RHIC at 250 GeV or in LHC at 7 TeV*. Coherent Electron Cooling was suggested early 1980s as a possibility for using various microwave instabilities in an electron beam to enhance its interaction with hadrons**. The capabilities of present-day accelerator technology, ERLs, and high-gain Free-Electron Lasers (FELs), finally caught up with the idea and provided the all necessary ingredients for realizing such a process at energies typical for modern high energy hadron colliders. In this paper, we discuss the principles, the main limitations of this scheme and present some predictions for Coherent Electron Cooling in RHIC and the LHC operating with ions or protons.
*V. N. Litvinenko, Y. S. Derbenev, Proc. 29th Int. FEL Conference, Novosibirsk, August, 2007. |
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| WEPP011 | Setup and Performance of RHIC for the 2008 Run with Deuteron and Gold Collisions | 2548 |
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| This year deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for this run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity since the 2003 run. | ||
| WEPP019 | RHIC Polarized Proton Performance in Run-8 | 2566 |
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| During Run-8, the Relativistic Heavy Ion Collider (RHIC) provided collisions of spin-polarized proton beams at two interaction regions. Helical spin rotators at these two interaction regions were used to control the spin orientation of both beams at the collision points. Physics data were taken with different orientations of the beam polarization. We present recent developments and improvements as well as the luminosity and polarization performance achieved during Run-8. | ||
| THPC042 | Uncoupled Achromatic Tilted S-bend | 3071 |
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A particular section of one of the electron beam transport lines, to be used in the e-cooling project* of the Relativistic Heavy Ion Collider (RHIC), is constrained to bend the beam simultaneously in both the horizontal and vertically planes and also be achromatic in both planes. The simultaneous horizontal and vertical achromatic bend is accomplished by rotating, about the longitudinal axis of the beam, the dipole and quadrupole elements of this section of the line. However such a rotation of the magnetic elements may couple the transported beam through the first order beam transfer matrix (linear coupling). In this paper we investigate for a sufficient condition, that the first order transport matrix (R-matrix) can satisfy, under which such a section of a beam transfer line is both achromatic and also constrains the beam at the exit of the line to emerge linearly uncoupled. We also provide a complete solution for the beam optics, of this part of the beam transfer line, which satisfies achromaticity and no first order beam coupling.
*htpp://www.bnl.gov/cad/eRhic/Documents/AD_Position_Paper_2007.pdf |
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| THPC085 | VORPAL Simulations Relevant to Coherent Electron Cooling | 3185 |
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Coherent electron cooling (CEC)* combines the best features of electron cooling and stochastic cooling, via free-electron laser technology**, to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the “modulator” and “kicker” regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations*** of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results. In particular, we compare the semi-analytic binary collision model with electrostatic particle-in-cell (PIC).
*Ya. S. Derbenev, COOL ’07 Proc. (2007). |