Nonlinear Behavior of a Shim Coil in an LTS/HTS NMR Magnet With an HTS Insert Comprising Double-Pancake HTS-Tape Coils

Author

Hahn, Seung-Yong ; Ahn, Min Cheol ; Bascuñán, Juan ; Yao, Weijun ; Iwasa, Yukikazu

Author_Institution

Francis Bitter Magn. Lab., Massachusetts Inst. of Technol., Cambridge, MA, USA

Volume

19

Issue

3

fYear

2009

fDate

6/1/2009 12:00:00 AM

Firstpage

2285

Lastpage

2288

Abstract

This paper reports results, experimental and analytical, of the nonlinear behavior of a shim coil in the presence of an HTS coil assembled with double-pancake (DP) HTS-tape coils. The experimental results are from: 1) operation of a 700 MHz LTS/HTS NMR magnet (LH700) consisting of a 600 MHz LTS NMR magnet (L600) equipped with superconducting shim coils and a 100 MHz DP-assembled HTS insert (H100) and; 2) an experiment with a room-temperature (RT) Z1 shim coil coupled to a 50 MHz DP-assembled HTS insert (H50). A field mapping theory with a harmonic analysis is applied to interpret both results. Based on experimental results and analyses, we conclude that the screening-current-induced field (SCF) generated by a DP-assembled HTS insert is primarily responsible for the nonlinear behavior, including strength degradation, of a shim coil.

Keywords

high-temperature superconductors; nuclear magnetic resonance; shims; superconducting coils; superconducting magnets; superconducting tapes; HTS insert; LTS/HTS NMR magnet; double-pancake HTS-tape coils; field mapping theory; frequency 600 MHz; frequency 700 MHz; harmonic analysis; nonlinear behavior; screening current-induced field; superconducting shim coils; temperature 293 K to 298 K; Double-pancake coils; HTS insert; LTS/HTS NMR magnet; field homogeneity; nonlinear behavior of a shim coil; screening-current-induced field;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2009.2018809

Filename

5153105