Thermal stability of high-strength Nb_3Sn wire and relevant application to the cryocooled superconducting magnet

高强度Nb_3Sn线材的热稳定性及其在低温超导磁体中的应用

基本信息

批准号：
11555083
负责人：
WATANABE Kazuo
金额：
$ 6.08万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555083/
关键词：
Nb_3Sn CuNb high strength thermal stability cryogenic stability superconducting magnet helium-free GM-cryocooler

项目摘要

A test coil employing CuNb/Nb_3Sn multifilament superconducting wire was prepared, and the cryogenic stability for the CuNb/Nb_3Sn coil was examined in liquid helium cooling and cryocooler cooling conditions. It is found that a minimum quench energy MQE in the cryocooling condition is reduced to 1/3 in comparison with the liquid helium cooling condition, and on the contrary a normal zone propagation velocity is enlarged by a factor of 3 to 4. These behaviors are dependent on the loading current ratio between the operation current and the critical current, and in particular the cryocooling condition reveals the strong dependence of the current ratio.Further, the CuNb/Nb_3Sn test coil fabricated by a react and wind technique was investigated in a large electromagnetic stress state. It is found that the test coil wound by the bending strain of 0.33% stood with the Hoop stress of 330Mpa, and that no degradation of the critical current for the test coil was observed. This surely results in confirmation of the patent for the CuNb/Nb_3Sn wire with reinforcing stabilizer.Finally, we started to construct the world's first cryogen-free hybrid magnet consisting of an outer cryogen-free compact wide bore superconducting magnet and an inner water-cooled resistine magnet. A cryogen-free 23 T hybrid magnet by the combination of a cryogen-free 8 T superconducting magnet with a 360mm warm bore magnet and a 15T water-cooled magnet will realize in near future.

准备了使用CUNB/NB_3SN多齿超导线的测试线圈，并在液体氦冷却和冷冻冷却器冷却条件下检查了CUNB/NB_3SN线圈的低温稳定性。发现与液体氦冷却条件相比，在冷冻条件下的最小淬灭能量MQE降低至1/3，相反，正常区域的传播速度由3至4的因子扩大。这些行为取决于操作电流和临界电流之间的负载比率依赖于强度的电流，并且依赖于较大的电流效果。在大型电磁应力状态下研究了由反应和风技术制造的CUNB/NB_3SN测试线圈。已经发现，弯曲应力为0.33％的测试线圈缠绕为330MPa的箍应力，并且未观察到测试线圈的临界电流降解。这肯定会导致用加强稳定剂确认CUNB/NB_3SN线的专利。从本文中，我们开始构建世界上第一个由无冰冷的无冰冷的宽孔超导管磁铁和内部水冷抗性抗性磁铁组成的世界上第一个无低温的混合动力磁铁。通过无低温8 T超导磁铁和360mm温暖的钻头和15T水冷磁铁的组合，无冰冷的23 T杂种磁铁将在不久的将来实现。