A new RHQT Nb3Al superconducting wire with a Ta/Cu/Ta three-layer filament-barrier structure
A new RHQT Nb3Al superconducting wire with a Ta/Cu/Ta three-layer filament-barrier structure
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DOI：
10.1088/0953-2048/25/6/065016
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发表时间：
2012-04
影响因子：
3.6
通讯作者：
T. Takeuchi;K. Tsuchiya;K. Nakagawa;S. Nimori;N. Banno;Y. Iijima;A. Kikuchi;T. Nakamoto
中科院分区：
文献类型：
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作者：
T. Takeuchi;K. Tsuchiya;K. Nakagawa;S. Nimori;N. Banno;Y. Iijima;A. Kikuchi;T. Nakamoto
为了抑制低磁场不稳定性（磁通跳跃在低磁场中）的快速加热，淬火和转变（RHQT）处理的Nb 3Al超导体，我们以前修改了截面设计的RHQT Nb 3Al通过采用钽势垒结构。与Nb障碍，Ta障碍不是超导的磁场在4.2 K，使他们电磁去耦丝。然而，小通量跳跃仍然发生在1.8 K，这是一个典型的工作温度的磁铁中使用的高能粒子加速器。此外，在相邻的Ta涂覆的双辊（JR）长丝之间的Ta/Ta界面处的不良结合经常导致前体丝在拉伸期间断裂。为了克服这些问题，我们制作了一种新的RHQT Nb 3Al线与Ta/Cu/Ta三层的阻挡层结构，其中的内部稳定技术（Cu棒包裹在Ta分散在线的横截面）进行了扩展。去除中间阻挡层（JR细丝/Ta/Cu/Ta/JR细丝）中的Ta/Ta界面允许前体丝被拉伸而不断裂。此外，铜丝屏障电磁解耦丝抑制磁通跳跃在1.8 K。韧性Cu层也提高了RHQT Nb_3Al的弯曲应变容限。
To suppress the low-magnetic-field instability (flux jumps in low magnetic fields) of a rapid-heating, quenching and transformation (RHQT) processed Nb3Al superconductor, we had previously modified the cross-sectional design of an RHQT Nb3Al by adopting a Ta filament-barrier structure. Unlike Nb barriers, Ta barriers are not superconducting in magnetic fields at 4.2 K so that they electromagnetically decouple filaments. However, small flux jumps still occurred at 1.8 K, which is a typical operating temperature for the magnets used in high-energy particle accelerators. Furthermore, poor bonding at the Ta/Ta interface between neighboring Ta-coated jelly-roll (JR) filaments frequently caused precursor wires to break during drawing. To overcome these problems, we fabricated a new RHQT Nb3Al wire with a Ta/Cu/Ta three-layer filament-barrier structure for which an internal stabilization technique (Cu rods encased in Ta are dispersed in the wire cross section) was extended. Removing the Ta/Ta interface in the interfilamentary barrier (JR filament/Ta/Cu/Ta/JR filament) allowed precursor wires to be drawn without breaking. Furthermore, the Cu filament barrier electromagnetically decoupled filaments to suppress flux jumps at 1.8 K. The ductile Cu layer also improved the bending strain tolerance of RHQT Nb3Al.