Comparison of different configurations of NbTi magnetic lenses
Comparison of different configurations of NbTi magnetic lenses
复制标题
NbTi磁透镜不同配置的比较
DOI：
10.1088/0953-2048/24/10/105012
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发表时间：
2011
影响因子：
3.6
通讯作者：
木吉司
中科院分区：
文献类型：
--
作者：
張治宇;松本真治;崔世鎔;寺西亮;木吉司
磁透镜是利用超导体的抗磁性来集中磁通量的新装置。用NbTi薄片制作了两种磁透镜，并对其进行了测量和系统的研究。A型通过堆叠具有相同外径和增加内径的NbTi环以形成中空圆锥体来构造。每一个圆环上都有一个缝隙，用来抑制圆周电流。测试了A型的三种构造方法：将环堆叠成其狭缝对齐但环之间没有绝缘（A-1），将环的狭缝对齐且环之间绝缘（A-2），以及将环的狭缝在不同位置且环之间绝缘（A-3）。对于类型B，片材被卷成空心圆锥体。将三个相同的锥体堆叠以形成透镜（B-1），并且将单个锥体用作参考透镜（B-2）。将透镜组装在具有NbTi磁体的低温冷却器冷却的低温恒温器中。测量了猝灭行为、浓度比、滞后和衰减行为。由于尺寸较大，B型的浓度比（B-1为2.49）大于A型（A-1为1.87）。两种透镜（类型A和B-1）在集中通量密度达到约0.64 T时淬火。结果表明，淬火是由NbTi片本身引起的。
Magnetic lenses are new devices that concentrate magnetic flux by using the diamagnetism of superconductors. Magnetic lenses of two types made from NbTi sheets were constructed; measurements were made on them and they were systematically studied. Type A was constructed by stacking NbTi rings that had identical outer diameters and increasing inner diameters to form a hollow cone. Each ring had a slit to suppress the circumference current. Three construction methods for type A were tested: the rings were stacked with their slits aligned but with no insulation between the rings (A-1), with their slits aligned and with insulation between the rings (A-2), and with their slits in different positions and with insulation between the rings (A-3). For type B, sheets were rolled into hollow cones. Three identical cones were stacked to form a lens (B-1) and a single cone was used as a reference lens (B-2). The lenses were assembled in a cryocooler-cooled cryostat with a NbTi magnet. The quenching behavior, concentration ratio, hysteresis, and decay behavior were measured. Because of its larger dimensions, type B had a larger concentration ratio (2.49 for B-1) than type A (1.87 for A-1). Both lenses (types A and B-1) were quenched when the concentrated flux density reached about 0.64 T. The results suggest that quenching was caused by the NbTi sheet itself.