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

在第一年，我们指出了制造高场磁铁的两个问题。一个问题是，为了获得高场，需要用环氧树脂来紧固线圈，另一个问题是，使用外部马氏体时效钢来增强磁线的有效抗拉强度。考虑到这些因素，我们用缠绕铜丝的方法生产了直径为20 mm的60T磁场。第二年，我们测试了最大磁场的拉伸强度随时间的变化关系。结果表明，通过将铜丝改为铜银丝，可以在直径18 mm的范围内获得71T的能量。去年，我们对71T磁体的重复性和耐用性进行了检查，发现该磁体可以连续产生8次69T的场强。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强度测量。为了获得更高的磁场，我们在71T磁体中设置了一个附加线圈。得到的最大场强为77T，直径为13.5 mm。根据我们的分析，77T应分为8T的内线圈和69T的外磁铁。这对于外部磁铁来说不是很有效。假设不能忽视内线圈对外线圈的影响，则应采用马氏体时效钢加固内线圈以获得更高的电场。获得的最大场强为80.3T，直径10.5 mm，这是世界纪录。在这种情况下，外磁体产生71T场，这一结果可以看作是一个有效的情况。结果表明，马氏体时效钢对每个线圈的强化可实现100T磁体，本研究课题有望在不久的将来实现。

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.