Magnetization measurement by use of non-destructive magnet up to 100 Tesla

在第一年，我们指出了制造高磁场磁体的两个问题。一个问题是为了获得高磁场，必须用环氧树脂使线圈紧绷，另一个问题是利用马氏体时效钢从外部增强磁线的有效抗拉强度。考虑到这些因素，我们可以通过绕线的方式生产直径20mm的60t场。第二年，我们测试了最大场的抗拉强度依赖性。因此，我们可以将Cu-wire改为Cu-Ag-wire，在直径18mm内达到71T。去年，我们检查了71t磁铁的再现性和耐用性，发现磁铁可以连续产生8次69t磁场。根据这一结果，我们在液氦温度高达65T的情况下进行了磁化测量。为了获得更高的磁场，我们在71t磁铁中设置了附加线圈。获得最大视场77T，直径13.5mm。根据我们的分析，77T应该分为8T的内线圈和69T的外磁铁。这对外磁体是无效的。假设不能忽视内圈对外圈的影响，应采用马氏体时效钢加固内圈，以获得更高的场。获得的最大场径为80.3T，直径为10.5mm，创世界纪录。在这种情况下，外磁体产生71t的磁场，这个结果可以看作是一个有效的情况。根据研究结果，采用马氏体时效钢加固各线圈可实现100t磁体，在不久的将来将达到本研究的目的。

In first year, we pointed out two problems when one makes high field magnets. One problem is making coil tight by epoxy resign is necessary to obtain high field and the other is reinforcement by use of maraging steel from outside increases an effective tensile strength of the magnet wire. Taking these points into consideration, we can produce 60T-field with diameter of 20mm by winding Cu-wire.Second year, we tested the tensile sterength dependence of the maximum field. As a result, we can achieve at 71T within a diameter of 18mm by changing Cu-wire into Cu-Ag-wire.The last year, we checked reproducibility and durability of the 71T-magnet and found that the magnet can produce successive 8 shots of 69T-field. Following this result, we carried out magnetization measurement at liquid helium temperature up to 65T.We set an additive coil in the 71T-magnet to obtain higher magnetic field. Obtained maximum field is 77T with 13.5mm diameter. From our analysis, 77T should be separated into 8T of inner coil and 69T of outer magnet. This is not efficient for outer magnet. Supposed that we cannot neglect an effect from inner coil on outer one, we should obtain higher field by reinforcing inner coil with maraging steel. Obtained maximum field is 80.3T with 10.5mm diameter and this is world record. In this case, outer magnet produces 71T-field and this result can be regarded as an efficient case. Following the results, reinforcement of each coil by maraging steel can realizes 100T-magnet and the subject of this study will be attained in very near future.