A Cryogen-Free 25-T REBCO Magnet With the Extreme-No-Insulation Winding Technique
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21ja112_full.pdf
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Author(s)
Park, Dongkeun
Lee, Wooseung
Bascuñán, Juan
Kim, Ho Min
Iwasa, Yukikazu
Date Issued
October 2021
Journal
IEEE Transactions on Applied Superconductivity
Publisher
IEEE
Abstract
We present the operation result of a cryogen-free 23.5 T/ϕ12.5 mm-cold-boremagnet prototype composed of a stack of 12 no-insulation (NI) REBCO single pancake coils—ten middle coils of 6-mm wide and two end coils of 8-mm wide tape—forming 6 double pancake (DP) coils with inner joints. Each coil was wound with the tape having only 1-μm-thick copper layer on each side to overcome the conductor thickness uniformity issue and enhance the mechanical strength within the winding, and then, additional electrical shunting by thin layers of solder was applied on the top and bottom surfaces of eachDPcoil for effective cooling and quench protection—called extreme-NI winding technique.With this small prototypemagnet towards a benchtop 1-GHzNMR,wevalidate our coil design that include conductor performance, screening-currentinduced field and stresses, and conduction-cooling cryogenics. Included in the paper are: 1) conductor issues and our counterproposal in winding; 2) screening-current reduction method; 3) design and manufacture summary of the magnet; and 4) operating test results of the magnet up to 25 Tesla.
Description
Submitted for publication in IEEE Transactions on Applied Superconductivity
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1109/tasc.2022.3161401
