| Paper |
Title |
Page |
| MOPP080 |
Studies of Breakdown in a Pressurized RF Cavity
|
736 |
| |
- 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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| WEPD022 |
High Field Superconductor for Muon Cooling
|
2455 |
| |
- J. Schwartz
NHMFL, Tallahassee, Florida
- R. P. Johnson, S. A. Kahn, M. Kuchnir
Muons, Inc, Batavia
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High temperature superconductors (HTS) have been shown to carry significant current density in the presence of extremely high magnetic fields when operated at low temperature. The successful design of magnets needed for high energy physics applications using such high field superconductor (HFS) depends critically on the detailed wire or tape parameters which are still under development and not yet well-defined. In the project reported here, we are developing HFS for accelerator use by concentrating on the design of an innovative magnet that will have a useful role in muon beam cooling. Measurements of available materials and a conceptual design of a high field solenoid using YBCO HFS conductor are being analyzed with the goal of providing useful guidance to superconductor manufacturers for materials well suited to accelerator applications.
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| WEPD023 |
Multi-purpose Fiber Optic Sensors for HTS Magnets
|
2458 |
| |
- J. Schwartz
NHMFL, Tallahassee, Florida
- R. P. Johnson, S. A. Kahn, M. Kuchnir
Muons, Inc, Batavia
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Magnets using new high temperature superconductor (HTS) materials are showing great promise for high magnetic field and/or radiation environment applications such as particle accelerators, NMR, and the plasma-confinement systems for fusion reactors. The development and operation of these magnets is limited, however, because appropriate sensors and diagnostic systems are not yet available to monitor the manufacturing and operational processes that dictate success. Optical fibers are being developed to be imbedded within the HTS magnets to monitor strain, temperature and irradiation, and to detect quenches. In the case of Bi2212, the fiber will be used as a heat treatment process monitor to ensure that the entire magnet has reached thermal equilibrium. Real-time measurements will aid the development of high-field magnets that are subject to large Lorentz forces and allow the effective detection of quenches so that the stored energy of operating magnets can be extracted and/or dissipated without damaging the magnet.
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