Persistent-mode operation and magnetization behavior of a solid-nitrogen-cooled MgB2 small-scale test coil towards a tabletop 1.5-T osteoporosis MRI

Author:

Choi YoonhyuckORCID,Park Dongkeun,Li YiORCID,Tanaka Hiromi,Lee Wooseung,Bascuñán Juan,Iwasa Yukikazu

Abstract

Abstract We present results—cool-down, energization, and persistent-mode operation—of a solid-nitrogen (SN2)-cooled, magnesium diboride (MgB2) small-scale test coil. The test coil, immersed in a volume of solid nitrogen at 6 K, successfully operated in persistent-mode at 108 A for a period of 5 d. Although designated a ‘persistent-mode’ coil, its center field was measured to decay at a rate of <0.6 ppm h−1, which is still considered low enough to meet the temporal stability requirement of <0.1 ppm h−1, for most magnetic resonance imaging magnets. This decay rate translates to a calculated circuit resistance of <1.79 × 10–12 Ω, which is mainly from one MgB2-MgB2 joint in the circuit. However, when the coil temperature increased from 6 to 16 K, the field had dropped by 0.33%: we believe this was caused by the change of magnetization in the MgB2 superconductor, which in turn decreased a screening-current field (SCF) at the magnet center. We performed a finite element analysis with a simplified numerical model based on H formulation to verify whether magnetization-induced SCF is responsible for this 0.33% drop. Indeed, the model shows that the change of magnetization, i.e. screening-current reduction and current density redistribution, happens during temperature-cycle-induced Jc (T) variation, and thus affects the center magnetic field. However, the Jc (T) variation in the 2nd cycle had little effect on MgB2 magnetization and thus had negligible magnetic field change.

Funder

National Institute of Biomedical Imaging and Bioengineering

Publisher

IOP Publishing

Subject

Materials Chemistry,Electrical and Electronic Engineering,Metals and Alloys,Condensed Matter Physics,Ceramics and Composites

Reference29 articles.

1. What is changed in the diagnosis of osteoporosis: the role of radiologists;Guglielmi;Quant. Imaging Med. Surg.,2018

2. X-Ray vs. CT vs. MRI,2020

3. Conductors for commercial MRI magnets beyond NbTi: requirements and challenges;Parizh;Supercond. Sci. Technol.,2017

4. Superconductivity at 39 K in magnesium diboride;Nagamatsu;Nature,2001

5. Review of the superconducting properties of MgB2;Buzea;Supercond. Sci. Technol.,2001

Cited by 10 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3