Quench Characteristics of bi2212 Solenoid Insert Coils in Background Field up to 20 T
Quench Characteristics of bi2212 Solenoid Insert Coils in Background Field up to 20 T
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bi2212 电磁铁插入线圈在高达 20 T 的背景场中的淬火特性
DOI：
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发表时间：
2011
影响因子：
1.8
通讯作者：
S. Chappell
中科院分区：
文献类型：
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作者：
Yifeng Yang;E. Young;I. Falorio;W. Bailey;C. Friend;A. Twin;S. Chappell
已证明使用缠绕和反作用bi 2212导线用于高场（>;20 T）插入线圈是一种有前途的技术。虽然低温稳定性和失超传播是超导磁体设计和安全运行的基本问题，但高场应用的数据很少。本工作显示的数据，从系统的淬火测量在4.2 K的两个6层300 mm高的bi 2212螺线管线圈在不同的电流I之间的50%和95%的IC在不同的背景场为15，18和20 T的大口径紧凑型NbTi-Nb 3Sn磁体由牛津仪器公司开发。淬火引起的局部热脉冲（20-100毫秒），并记录与时空分辨电压抽头和温度计。通过精确控制在热脉冲中传递的功率，获得每个测试条件下的准静态最小传播区MPZ的最小淬火能量MQE和时间常数。发现MQE在三种不同的线圈中遵循IC 2/I4的标度律。MPZ表现出预期的各向异性，主要在切向方向上延伸，并限制在一个单一的绕组层。传播也主要是沿着缠绕层，速度相对较慢，小于50 cm/s，径向传播速度甚至更低，约为3 mm/s。在本研究中，HTS线圈之间的相互作用，并与LTS背景场进行了测量，结果是高度相关的20 T加上高磁场磁铁与集成LTS和HTS线圈的设计。在bi 2212导线中电流共享的宽电流温度范围和低温下热容量的T3依赖性的背景下分析结果。
The use of wind and react bi2212 wire for high field ( >;20 T) insert coils has been demonstrated to be a promising technology. While cryogenic stability and quench propagation are fundamental issues for the design and safe operation of superconducting magnets there is little data for the high field application. The present work shows data from systematic quench measurements at 4.2 K on two 6-layer 300 mm high bi2212 solenoid coils at different currents I between 50% and 95% of IC in different background fields of 15, 18 and 20 T from a wide bore compact NbTi-Nb3Sn magnet developed by Oxford Instruments. The quench was induced by localized heat pulses (20-100 ms) and recorded with temporal-spatial resolved voltage taps and thermometers. By precise control of the power delivered in the heat pulse, the minimum quench energy MQE and the time constant for the quasi-stationary minimum propagation zone MPZ was obtained for each test condition. MQE was found to follow a scaling law of IC2/I4 in three different coils. The MPZ exhibited the expected anisotropy, extending predominately in the tangential direction and confined in a single winding layer. The propagation was also predominantly along the winding layer with a relatively slow velocity less than 50 cm/s, with an even lower radial propagation velocity of ~ 3 mm/s. In the present study, the interplay between the HTS coils and with the LTS background field were also measured and the results are highly relevant to the design of 20 T plus high field magnets with integrated LTS and HTS coils. The results were analysed in the context of a wide current temperature range for current sharing in the bi2212 wire and the T3 dependence of heat capacity at low temperatures.