Development of rotating magnetic field system for the beta-NMR method

研制了一套旋转磁场系统，用β射线探测核磁共振法测定磁矩的符号。旋转磁场是使用两个交叉的亥姆霍兹线圈在直角。两个线圈的交流电流的相位角偏移90度。因此，产生的磁场是圆极化的。通过调整相位角差，产生右旋或左旋圆极化磁场。利用拾波线圈证实了产生了包含线性分量的右旋或左旋磁场。大坂大学核物理研究中心利用自旋极化的20F核研究了系统的性能。得到的20F磁莫奈的符号为正，与文献报道的一致。

A rotating magnetic field system has been developed to determine the sign of magnetic moment by means of the beta-ray-detected nuclear magnetic resonance method. The rotating magnetic field is obtained using two crossed Helmholtz-like coils at right angles. The phase angles of the alternating currents for the two coils are shifted by 90 degree. Thus the resulting magnetic field is circularly polarized. By the adjustment of the phase-angle difference, a right- or left-circularly polarized magnetic field is produced. Productions of right-or left-rotating magnetic fields including a linear component were confirmed using pickup-coils.A performance of the system was studied with spin-polarized 20F nuclei at the Research Center for Nuclear Physics, Osaka University. The obtained sign of magnetic monet for 20F is positive and in agreement with the reported one.