110 research outputs found
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Magnets for the national spallation neutron source accumulator ring
The National Spallation Neutron Source Accumulator Ring will require large aperture dipole magnets, strong focusing quadrupole magnets, and smaller low field dipole, quadrupole, and sextupole correcting magnets. All of the magnets will provide a fixed magnetic field throughout the accumulator`s fill/storage/extraction cycle. Similar fixed field magnets will also be provided for the beam transport systems. Because of the high intensity in the accumulator, the magnets must be designed with high tolerances for optimum field quality and for the high radiation environment which may be present at the injection/extraction areas, near the collimators, and near the target area. Field specifications and field plots are presented as well as planned fabrication methods and procedures, cooling system design, support, and installation
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The RHIC injection kicker
Beam transfer from the AGS to RHIC is performed in single-bunch mode. Close spacing of the bunches in the collider requires an injection kicker with a rise time of <90 nsec, suggesting adoption of a travelling wave structure. The required vertical kick of 0.186 t{center_dot}m is provided by 4 magnets, each 1.12 m long with a 48.4 x 48.4 mm aperture and operated at 1.6 kA. The kicker is constructed as a {open_quotes}C{close_quotes} cross section magnet, in which ferrite and high-permittivity dielectric sections alternate. The dielectric blocks provide the capacity necessary for the nominally 25 {Omega} characteristic impedance of the travelling wave structure, but impose the practical limit on the peak voltage, and thus current, achievable. Computer studies to minimize local electric field enhancements resulted in a configuration capable of holding {approximately} 50 kV, with adequate safety margin over the nominal 40 kV. Equivalent circuit analysis indicated the possibility of lowering the nominal voltage by operating mismatched into 20 {Omega} terminations without degrading the pulse shape. In this paper, the experience gained in the fabrication of the production units and the results from various single-unit tests and operation of four kickers with beam in the {open_quotes}Sextant Test{close_quotes} are reported
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Small gap magnets and vacuum chambers for eRHIC
eRHIC[1][2][3], a future high luminosity electron-ion collider at Brookhaven National Laboratory (BNL), will add polarized electrons to the list of colliding species in RHIC. A 10-30 GeV electron energy recovery linac (ERL) will require up to six passes around the RHIC 3.8 km circumference. We are developing and testing small (5 mm) gap dipole and quadrupole magnets and vacuum chambers for cost-effective eRHIC passes [4]. We are also studying the sensitivity of eRHIC pass optics to magnet and alignment errors in such a small magnet structure. We present the magnetic and mechanical designs of the small gap eRHIC components and prototyping test progress
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AN OVERVIEW OF THE SNS ACCELERATOR MECHANICAL ENGINEERING.
The Spallation Neutron Source (SNS*) is an accelerator-based neutron source currently nearing completion at Oak Ridge National Laboratory. When completed in 2006, the SNS will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. SNS is a collaborative effort between six U.S. Department of Energy national laboratories and offered a unique opportunity for the mechanical engineers to work with their peers from across the country. This paper presents an overview of the overall success of the collaboration concentrating on the accelerator ring mechanical engineering along with some discussion regarding the relative merits of such a collaborative approach. Also presented are a status of the mechanical engineering installation and a review of the associated installation costs
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STATUS OF FAST IR ORBIT FEEDBACK AT RHIC.
To compensate modulated beam-beam offsets caused by mechanical vibrations of IR triplet quadrupoles at frequencies around 10 Hz, a fast IR orbit feedback system has been developed. We report design considerations and recent status of the system
Higher order mode damper for low energy RHIC electron cooler SRF booster cavity
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon,
the Low Energy RHIC electron Cooler (LEReC) is currently under commissioning at
BNL. The Linac of LEReC is designed to deliver a 1.6 MeV to 2.6 MeV electron
beam, with rms dp/p less than 5e-4. A 704 MHz superconducting radio frequency
(SRF) booster cavity in this Linac provides up to 2.2 MeV accelerating voltage.
With such a low energy and very demanding energy spread requirement, control of
Higher Order Modes (HOMs) in the cavities becomes critical and needs to be
carefully evaluated to ensure minimum impact on the beam. In this paper, we
report the multiphysics design of the HOM damper for this cavity to meet the
energy spread requirement, as well as experimental results of the cavity with
and without the HOM damper.Comment: 9 pages, 7 figure
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