Test of an 8.66-T REBCO Insert Coil With Overbanding Radial Build for a 1.3-GHz LTS/HTS NMR Magnet

被引：57

作者：

Qu, Timing ^{[1
,2
,3
]}

Michael, Philip C. ^{[1
]}

Bascunan, Juan ^{[1
]}

Lecrevisse, Thibault ^{[1
]}

Guan, Mingzhi ^{[1
]}

Hahn, Seungyong ^{[4
,5
]}

Iwasa, Yukikazu ^{[1
]}

机构：

[1] MIT, Francis Bitter Magnet Lab, Plasma Sci & Fus Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA

[2] Tsinghua Univ, Dept Mech Engn, Beijing 100084, Peoples R China

[3] Tsinghua Univ, State Key Lab Tribol, Beijing 100084, Peoples R China

[4] Natl High Magnet Field Lab, Tallahassee, FL 32306 USA

[5] Florida State Univ, Tallahassee, FL 32306 USA

来源：

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY | 2017年 / 27卷 / 04期

基金：

美国国家卫生研究院; 中国国家自然科学基金;

关键词：

NMR magnet; no-insulation; double pancake; overbanding; FIELD;

D O I：

10.1109/TASC.2016.2633626

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

A 1.3-GHz/54-mm LTS/HTS NMR magnet, assembled with a three-coil (Coils 1-3) 800-MHz HTS insert in a 500-MHz LTS NMR magnet, is under construction. The innermost HTS insert Coil 1 has a stack of 26 no-insulation (NI) double pancake (DP) coils wound of 6-mm-wide and 75-mu m-thick REBCO tapes. In order to keep the hoop strains on REBCO tape <0.6% at an operating current I-op of 250 A and in a field of 30.5 T, we overbanded each pancake in Coil 1 with a 6-mm-wide, 76-mu m-thick 304 stainless steel strip: 7-mm-thick radial build for the central 18 pancakes, while 6-mm-thick for the outer 2 x 17 pancakes. In this paper, Coil 1 was successfully tested at 77 K and 4.2 K. In the 77-K test, the measured critical current was 35.7 A, determined by an E-field criterion of 0.1 mu V/cm. The center field magnet constant decreased from 34.2 to 29.3 mT/A, when I-op increased from 5 to 40 A. The field distribution at different I-op along the z-axis was measured. The residual field distributions discharged from 10 and 20 A were recorded. In the 4.2-K test, Coil 1 successfully generated a central field of 8.78 T at 255 A. The magnet constant is 34.4 mT/A, which is same as our designed value. The field homogeneity at the coil center within a +/- 15-mm region is around 1700 ppm. This large error field must be reduced before field shimming is applied.

引用

页数：5