Development of Novel Experimental Method by Polarized Neutrons

极化中子新实验方法的发展

基本信息

批准号：
05044031
负责人：
ENDOH Yasuo
金额：
$ 6.4万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

When we initiated this project, we aimed construction of two main subjects : One is the so called a new version of neutron spin echo, and the other is the neutron polaritometry. Both were already developed at Institute Laue Langevin (ILL), but the High Flux Reactor of ILL have been shut down for long due to the replacement of the reactor vessel.Since Japanese neutron scattering scientists were eager to develop the experimental techniques utilizing polarized neutrons, it is a good opportunity to collaborate with the ILL scientists by inviting to this project of the technical development of polarized neutrons. We have been pushing hard two subjects and we could make at least one very successfully. We explain briefly the results what we have developed in the two years' period.The principle of the Neutron Spin Echo (NSE) method is that the Larmor precession of neutron spin around the steady magnetic field can be used as standard 'clock' besides 'velocity' of neutron flux. When polarized ne … More utrons pass through two magnetic channels in which the magnetic field is very identical through two channels. Then at the center of two channels, neutron spin rotation is forced to completely reverse. Eventually neutron polarization at just the outlet of the second magnetic channel is back to the same state of the polarization at the inlet of the first channel, which is called Echo. This principle was applied to the real NSE machine, with which we investigate the high resolution neutron spectroscopy combined with cold neutron source. Here we challenge a new version of NSE spectroscopy by using thermal neutrons as well as triple axis spectrometer. Since neutron velocity is larger and neutron path is not symmetric geometrically before and after the sample position, the echo condition is hard to realize. However the ILL scientists developed a number of new ideas but they had no chance to prove experimentally. In this project we both constructed a prototype NSE machine, which is set on the 3-axis spectrometer of PONTA (5G port of JRR3). and searched many points to be solved. Finally we have tested the performance of this NSE method and concluded the good sensitivity in energy resolution as well as the feasibility of the novel NSE technique itself.As for the neutron polaritometry, we have encountered unexpected difficulty of getting high quality polarizer, which have been installed at the triple axis spectrometer of TOPAN (6G port of JRR3). Therefore we have investigated how to improve neutron polarization mostly, from which we conclude now that the polarization can be improved as we aimed initially. Less

当我们启动这个项目时，我们瞄准了两个主要主题的构造：一个是所谓的中子自旋回声的新版本，另一个是中子极化测定法。两者都已经在Laue Langevin研究所开发，但是由于替换了反应堆船只，生病的高磁反应堆已被关闭了很长时间。由于日本中子散射科学家渴望使用偏光性中子开发实验技术，这是一个很好的机会，可以通过邀请型号的科学家合作，以邀请这种技术开发这些项目的技术开发项目。我们一直在努力工作两个主题，我们至少可以非常成功地制造一个主题。我们简要解释了我们在两年时间内开发的结果。中子自旋回波（NSE）方法的原理是，围绕稳定磁场的中子旋转的Larmor进度可以用作标准的“时钟”，除了中子通量的“速度”。当极化NE…越多的Utron穿过两个磁道通道，其中磁场通过两个通道非常相同。然后在两个通道的中心，中子自旋旋转被迫完全逆转。最终，仅第二个磁道通道的出口处的中子极化又回到了第一个通道入口处的极化状态，这称为回声。该原理应用于真实的NSE机器，我们研究了高分辨率中子光谱与冷中子源结合的高分辨率中子。在这里，我们通过使用热中子和三轴光谱仪来挑战新版本的NSE光谱。由于中子速度更大，并且中子路径在样品位置之前和之后不是对称的几何形式，因此很难实现回声条件。但是，病态的科学家们提出了许多新想法，但他们没有机会通过实验证明。在这个项目中，我们俩都构建了一个原型NSE机器，该机器设置在Ponta（JRR3的5G端口）的3轴光谱仪上。并搜索了许多要解决的点。最后，我们测试了这种NSE方法的性能，并得出结论能量分辨率的良好敏感性以及新型NSE技术本身的可行性。作为中子极化测量法，我们遇到了获得高质量极化器的意外困难，这些偏光层已安装在TopAN的三轴光谱仪（6G JRR3）。因此，我们已经投资了如何改善中子两极化的主要原因，现在我们可以从中获得，因为我们最初的目标可以改善两极分化。较少的