Development and application of a neutron polarizing and focusing system based on magnetic field gradients

在这项研究中，我们已经开发了一个中子极化和聚焦装置的基础上的相互作用的中子磁矩和磁场，我们使用四极和六极磁铁，分别来收集和聚焦中子。该装置被认为是有用的小角极化中子散射实验与聚焦几何。中子极化器是一个扩展的Halbach型四极磁铁，内径为15 mm，长度为2,200 mm。四极磁铁内部的磁场梯度测量为~150 T/m。在JRR-3的C3-1-2-1束线上建立了由四极磁铁和两个六极磁铁组成的中子极化聚焦装置，并进行了脉冲中子极化聚焦试验。实验结果表明，脉冲中子可以聚焦在0.8 ~ 1.05nm的波长范围内。中子极化聚焦装置已确定安装在日本PARC的小角中子散射仪上。

In this study, we have developed a neutron polarizing and focusing device based on interaction between a neutron magnetic moment and a magnetic field, where we use quadrupole and sextupole magnets to polarize and focus neutrons, respectively. The device is considered useful for small angle polarized neutron scattering experiments with focusing geometry. The neutron polarizer is an extended Halbach-type quadrupole magnet with an inner diameter of 15 mm and length of 2,200 mm. The magnetic field gradient inside the quadrupole magnet was measured to be ~150 T/m. We set up the neutron polarizing and focusing device composed of the quadrupole magnet and two sextupole magnets at the beamline C3-1-2-1 of JRR-3, and performed pulsed neutron polarizing and focusing test. As the result, we could focus the pulsed neutrons in the wavelength range from 0.8 to 1.05 nm. The neutron polarizing and focusing device has been determined to be installed to a small angle neutron scattering instrument of J-PARC.