First performance test of a 25 T cryogen-free superconducting magnet
First performance test of a 25 T cryogen-free superconducting magnet
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DOI：
10.1088/1361-6668/aa6676
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发表时间：
2017-06-01
影响因子：
3.6
通讯作者：
Ioka, Shigeru
中科院分区：
文献类型：
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作者：
Awaji, Satoshi;Watanabe, Kazuo;Ioka, Shigeru
一台25T无低温超导磁体(25T-CSM)被研制并安装在东北大学研究所超导材料强场实验室(HFLSM)。25T-CSM由高温超导(HTS)线圈和低温超导(LTS)线圈组成。中间LTS截面线圈采用高强度CuNb/Nb3SnRutherford电缆，配以增强稳定剂CuNb复合材料。所有的线圈都用环氧树脂浸渍以进行传导冷却。首先设计了GdBa2Cu3Oy(Gd123)线圈作为高温超导插入线圈，然后又研制出了Bi2Sr2Ca2Cu3Oy(Bi2223)线圈。HTS插件和LTS(CuNb/Nb3Sn和NbTi)出线线圈分别由两台4K GM和两台GM/JT制冷机冷却。在854A的工作电流下，LTS线圈成功地产生了14T的中心磁场，而没有任何训练失超。在没有背景场的情况下，Gd123线圈在132.6 A的工作电流下产生了10.15T的电流。随后，在14T的本底磁场下，Gd123插件的工作电流逐步增加。Gd123线圈的工作电流可以稳定地工作到124.0 A，相当于23.55T，但在124.6 A(23.61T)左右淬火。使用镍合金增强Bi2223带材的Bi2223插入线圈在单机测试中的工作电流为204.7 A时成功地产生了11.48T的中心磁场，在14T的背景磁场中成功地产生了24.57T的中心磁场，Gd123插入件的中心磁场计算值与实测值相差约0.4T，Bi2223插入件的中心磁场计算值与实测值相差约0.1T。
A 25 T cryogen-free superconducting magnet (25T-CSM) was developed and installed at the High Field Laboratory for Superconducting Materials (HFLSM), IMR, Tohoku University. The 25T-CSM consists of a high-temperature superconducting (HTS) coil and a low-temperature superconducting (LTS) coil. A high-strength CuNb/Nb3Sn Rutherford cable with a reinforcing stabilizer CuNb composite is adopted for the middle LTS section coil. All the coils were impregnated using an epoxy resin for conduction cooling. Initially, a GdBa2Cu3Oy (Gd123) coil was designed as the HTS insert coil, and then a Bi(2)Sr(2)Ca(2)Cu(3)Oy (Bi2223) coil was also developed. The HTS insert and the LTS (CuNb/Nb3Sn and NbTi) outsert coils are cooled by two 4K GM and two GM/JT cryocoolers, respectively. The LTS coils successfully generated a central magnetic field of 14 T at an operating current of 854 A without any training quench. The Gd123 coil generated 10.15 T at an operating current of 132.6 A in the absence of a background field. Subsequently, the operating current of the Gd123 insert was increased in a step-by-step manner under a background field of 14 T. The Gd123 coil could be operated up to 124.0 A stably, which corresponds to 23.55 T, but quenched at around 124.6 A (23.61 T). The Bi2223 insert coil using a Ni-alloy reinforced Bi2223 tape successfully generated 11.48 T at an operation current of 204.7 A in a stand-alone test and 24.57 T in a background field of 14 T. The differences between the calculated and the measured values of the central magnetic fields are about 0.4 T for the Gd123 insert and 0.1 T for the Bi2223 insert around 24 T.