Curvature, Hydrogen, Q

Journal Article · Thu Mar 31 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3580648· OSTI ID:21516673

Wallace, John Paul ^[1]; Myneni, Ganapati Rao ^[2]; Pike, Robert ^[3]

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1. Casting Analysis Corp., Weyers Cave, VA 24486 (United States)
2. Jefferson Lab, Newport News, VA 23606 (United States)
3. College of William and Mary, Williamsburg, VA 23187 (United States)

The manufacturing of niobium SRF accelerator cavities is plagued by a mobile point defect, hydrogen. For efficient accelerator operation, niobium must function at both high electric and magnetic fields, and is compromised if magnetic impurities are located in the surface regions of the material. The finding that trace hydrogen in niobium can produce structures with magnetic properties is a feature that is not acceptable for a high performance cavity. X-ray diffraction has proved to be the key tool in assessing irreversible process damage to the niobium substrate. In future generations of accelerators, niobium will actually be merely the substrate for more effective superconductors that will allow for more efficient operation. The substrate analogy to the silicon wafer industry is useful since for niobium it may be possible to avoid some of the mistakes made in silicon technology. Because hydrogen attacks niobium on a number of different size scales, there is an inherent complexity in the trouble sources. There are also features in cavity design that are benign, such as local curvature considerations, requiring a fully non symmetric analysis of current flow to be appreciated.

• OSTI ID: 21516673
• Journal Information: AIP Conference Proceedings, Vol. 1352, Issue 1; Conference: 1. international symposium on the superconducting science and technology of ingot niobium, Newport News, VA (United States), 22-24 Sep 2010; Other Information: DOI: 10.1063/1.3580648; (c) 2011 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACCELERATORS
CAVITIES
DESIGN
HYDROGEN
IMPURITIES
INDUSTRY
IRREVERSIBLE PROCESSES
MAGNETIC FIELDS
MAGNETIC PROPERTIES
MANUFACTURING
NIOBIUM
OPERATION
POINT DEFECTS
SILICON
SUBSTRATES
SUPERCONDUCTORS
SURFACES
SYMMETRY
X-RAY DIFFRACTION
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIFFRACTION
ELEMENTS
METALS
NONMETALS
PHYSICAL PROPERTIES
REFRACTORY METALS
SCATTERING
SEMIMETALS
TRANSITION ELEMENTS