Effects of core type, placement, and width on the estimated interstrand coupling properties of QXF-type Nb₃Sn Rutherford cables

Journal Article · Mon Jan 12 00:00:00 EST 2015 · IEEE Transactions on Applied Superconductivity

DOI:https://doi.org/10.1109/TASC.2015.2390628· OSTI ID:1213938

Collings, E. W. ^[1]; Sumption, M. D. ^[1]; Majoros, M. ^[1]; Wang, X. ^[2]; Dietderich, D. R. ^[2]

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1. The Ohio State Univ., Columbus, OH (United States)
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

The coupling magnetization of a Rutherford cable is inversely proportional to an effective interstrand contact resistance R_eff , a function of the crossing-strand resistance R_c, and the adjacent strand resistance R_a. In cored cables, R_eff continuously varies with W, the core width expressed as percent interstrand cover. For a series of un-heat-treated stabrite-coated NbTi LHC-inner cables with stainless-steel (SS, insulating) cores, R_eff (W) decreased smoothly as W decreased from 100%, whereas for a set of research-wound SS-cored Nb₃Sn cables, R_eff plummeted abruptly and remained low over most of the range. The difference is due to the controlling influence of R_c - 2.5 μΩ for the stabrite/NbTi and 0.26 μΩ for Nb₃Sn. The experimental behavior was replicated in the R_eff (W)’s calculated by the program CUDI, which (using the basic parameters of the QXF cable) went on to show in terms of decreasing W that: 1) in QXF-type Nb₃Sn cables (R_c = 0.26 μΩ), R_eff dropped even more suddenly when the SS core, instead of being centered, was offset to one edge of the cable; 2) R_eff decreased more gradually in cables with higher R_c’s; and 3) a suitable R_eff for a Nb₃Sn cable can be achieved by inserting a suitably resistive core rather than an insulating (SS) one.

• Research Organization: The Ohio State Univ., Columbus, OH (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0011721
• OSTI ID: 1213938
• Journal Information: IEEE Transactions on Applied Superconductivity, Vol. 25, Issue 3; ISSN 1051-8223
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Country of Publication: United States
• Language: English

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