August 27, 2017 to September 1, 2017
RAI Congress Center, Amsterdam, The Netherlands
Europe/Amsterdam timezone

A Field-Shaking System to Eliminate the Screening-Current Field in the 800-MHz HTS Insert of the MIT 1.3-GHz LTS/HTS NMR Magnet: A Small-Model Study

Aug 28, 2017, 1:15 PM
1h 45m
Posters Area

Posters Area

Poster Presentation of 1h45m C3 - HTS Insert and Model Magnets Mon-Af-Po1.03


Jiho Lee (Massachusetts Institute of Technology)


In this paper, we present results, experimental and analytical, of a small-model study, from which we plan to develop and apply a full-scale field-shaking system to minimize or even eliminate the screening current-induced field (SCF) in the 800-MHz HTS Insert (H800) of the MIT 1.3-GHz LTS/HTS NMR magnet (1.3G) currently under construction—the H800 is composed of 3 nested coils, each a stack of no-insulation (NI) REBCO double-pancakes. In 1.3G, H800 is the chief source of a large error field generated by its own SCF. To study the effectiveness of the field-shaking technique, we use a set of 3-nested and series-connected coils (3-Coil Sample) composed of 3 NI REBCO double-pancakes, one from each of the 3 H800 coils, and place it in the bore of a 5-T/300-mm room-temperature bore external magnet (5TM). 5TM is used not only to induce SCF in the 3-Coil Sample but also eliminate it by the field-shaking. For each run, we induce SCF in the 3-Coil Sample at an axial location where the external radial field Br > 0, then for the field-shaking, move to another location where the external axial field Bz >> Br. To examine if other SCF eliminating techniques, e.g., the current-sweep-reversal (CSR) method, is applicable to H800 even when L500 and H800 are series-connected, we perform similar sequences of test for other combinations of the 3-Coil Sample axial locations. Additionally, we energize the 3-Coil Sample to study SCF dependence on transport current. In this paper, we report 77-K experimental results, develop an analysis that satisfactorily explains the results, and apply the analysis to design a field-shaking system for 1.3G at full operation.
Acknowledgment: Work supported by the National Institute of General Medical Sciences of the National Institutes of Health.

Submitters Country United States

Primary authors

Jiho Lee (Massachusetts Institute of Technology) Dongkeun Park (Massachusetts Institute of Technology) Philip Michael (Massachusetts Institute of Technology) Juan Bascuñán (Massachusetts Institute of Technology) Yukikazu Iwasa (Massachusetts Institute of Technology)

Presentation materials