| Paper |
Title |
Page |
| MOPP080 |
Studies of Breakdown in a Pressurized RF Cavity
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736 |
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- M. BastaniNejad, A. A. Elmustafa
Old Dominion University, Norfolk, Virginia
- M. Alsharo'a, P. M. Hanlet, R. P. Johnson, S. Korenev, M. Kuchnir, D. J. Newsham, R. Sah
Muons, Inc, Batavia
- C. M. Ankenbrandt, A. Moretti, M. Popovic, K. Yonehara
Fermilab, Batavia, Illinois
- D. M. Kaplan
Illinois Institute of Technology, Chicago, Illinois
- D. Li
LBNL, Berkeley, California
- D. Rose, C. H. Thoma, D. R. Welch
Voss Scientific, Albuquerque, New Mexico
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Previous studies of RF breakdown in a cavity pressurized with dense hydrogen gas have indicated that breakdown probability is proportional to a high power of the surface electromagnetic field. This behavior is similar to the Fowler-Nordheim description of electron emission from a cold cathode, and it implies that breakdown is a quantum mechanical effect that is characterized by the work function of the cavity metal. We describe our present efforts to measure the distributions of work functions at the nanoscale level on the surfaces of the electrodes used in breakdown studies, and to understand how the RF conditioning process affects them.
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| MOPP090 |
Incorporating RF into a Muon Helical Cooling Channel
|
760 |
| |
- S. A. Kahn, M. Alsharo'a, R. P. Johnson
Muons, Inc, Batavia
- D. R. Broemmelsiek, A. Jansson, V. Kashikhin, V. S. Kashikhin, A. L. Klebaner, G. F. Kuznetsov, G. V. Romanov, A. V. Shemyakin, D. Sun, K. Yonehara, A. V. Zlobin
Fermilab, Batavia, Illinois
- L. Thorndahl
CERN, Geneva
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A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides solenoidal, helical dipole and helical quadrupole fields has shown considerable promise in providing six-dimensional cooling for muon beams. The energy lost by muons traversing the gas absorber needs to be replaced by inserting RF cavities into the lattice. Replacing the substantial muon energy losses using RF cavities with reasonable gradients will require a significant fraction of the channel length be devoted to RF. However, to provide the maximum phase space cooling and minimal muon losses, the helical channel should have a short period and length. In this paper we shall examine three approaches to include RF cavities into the HCC lattice: - Use higher frequency cavities that can be placed inside the magnetic channel,
- Interleave cavities between magnetic coil rings, and
- Place banks of RF cavities between segments of HCC channels.
Each of these approaches has positive and negative features that need to be evaluated in selecting the proper concept for including RF into the HCC system.
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| MOPP105 |
Compact, Tunable RF Cavities
|
802 |
| |
- M. Popovic, C. M. Ankenbrandt, E. Griffin, A. Moretti, R. E. Tomlin
Fermilab, Batavia, Illinois
- M. Alsharo'a, I. B. Enchevich, R. P. Johnson, S. Korenev
Muons, Inc, Batavia
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New developments in the design of fixed-field alternating gradient (FFAG) synchrotrons have sparked interest in their use as rapid-cycling, high intensity accelerators of ions, protons, muons, and electrons. Potential applications include proton drivers for neutron or muon production, rapid muon accelerators, electron accelerators for synchrotron light sources, and medical accelerators of protons and light ions for cancer therapy. Compact RF cavities that tune rapidly over various frequency ranges are needed to provide the acceleration in FFAG lattices. An innovative design of a compact RF cavity that uses orthogonally biased ferrite for fast frequency tuning and liquid dielectric to adjust the frequency range is being developed using physical prototypes and computer models.
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| WEPD014 |
Magnets for the MANX 6-D Muon Cooling Demonstration Experiment
|
2434 |
| |
- V. S. Kashikhin, N. Andreev, V. Kashikhin, M. J. Lamm, K. Yonehara, A. V. Zlobin
Fermilab, Batavia, Illinois
- M. Alsharo'a, R. P. Johnson, S. A. Kahn, T. J. Roberts
Muons, Inc, Batavia
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MANX is a 6-dimensional muon ionization-cooling experiment that has been proposed to Fermilab to demonstrate the use of a helical cooling channel (HCC) for muon beam emittance reduction for future muon colliders and neutrino factories. The HCC for MANX has solenoidal, helical dipole, and helical quadrupole magnetic components, which diminish as the beam loses energy as it slows down in the liquid helium absorber inside the magnet. The proposed magnet system design is comprised of coil rings positioned along a helical path, which will provide the desired solenoidal and helical dipole and quadrupole fields. Additional magnets that provide emittance matching between the HCC and the upstream and downstream spectrometers are also described. The results of a G4Beamline simulation of the beam cooling behavior of the magnet and absorber system will be presented.
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| WEPD015 |
Design Studies of Magnet Systems for Muon Helical Cooling Channels
|
2437 |
| |
- V. Kashikhin, V. S. Kashikhin, M. J. Lamm, M. L. Lopes, A. V. Zlobin
Fermilab, Batavia, Illinois
- M. Alsharo'a, R. P. Johnson, S. A. Kahn
Muons, Inc, Batavia
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Helical cooling channels consisting of a magnet system with superimposed solenoid, helical dipole and quadrupole fields, and a pressurized gas absorber in the aperture, promise high efficiency in providing 6D muon beam cooling for a future Muon Collider and some other applications. Two alternative designs of the magnet system for the helical cooling channel are being investigated at the present time. The first one is based on a straight, large aperture solenoid with helical dipole and quadrupole coils. The other one is based on a spiral solenoid which generates the main solenoid field and the helical dipole and quadrupole components. Both concepts have been developed and compared for the MANX experiment. In this paper we continue design studies and comparison of these two concepts for the high field sections of a helical cooling channel. The results of magnetic and mechanical analysis as well as the superconductor choice and specifications will be presented and discussed.
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