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Development ofanewneutron spin echo spectrometer using multilayer spin splitters

使用多层自旋分裂器开发新型中子自旋回波谱仪

基本信息

批准号：
11480124
负责人：
TASAKI Seiji
金额：
$ 9.79万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11480124/
关键词：
neutron neutron spin echo spin flipper quasi elastic scattering multilayer spin splitter rfフリッパー

项目摘要

The multilayer spin splitter (MSS) is a multilayer consisting of a magnetic mirror, gap layer, and a non-magnetic mirror. When a neutron in a superposing state of magnetic parallel and anti-parallel component is incident to the MSS, a phase difference is introduced between the two spin components since the parallel andanti-parallel component is reflected by the different layer. This phase difference is equivalent to the Larmor precession angles of neutron in a magnetic field, in the quantum mechanical point of view. The aim of this study is to replace the huge magnet in neutron spin echo (NSE) instrument by MSS, and develop various types of new spin echo instruments.The results obtained in the present study are as follows :a. To replace precession magnetic field in NSE spectrometer, a pair of two MSS's should combine in (++) configuration so as to avoid the reduction of polarization due to beam divergence.b. Via magnetron sputtering technique, the homogeneity of the gap layer in MSS is about 7nm, which gives low polarisability for NSE spectrometer.c. On the contrary, vacuum evaporation technique gives us enough layer homogeneity. We have succeeded toperform preliminary NSE experiment using MSS 's.d. We have developed small resonance neutron spin flippers and succeeded to get NSE signal with the frequency up to 300kHz. These small resonance spin flippers, with low-magnetic field driven polarizing mirror, enables us to combine NSE instruments with other spectrometers, such as, reflectometers or small angle diffractometers.In order to apply these NSE instruments to spallation neutron source, we constructed the system to change the amplitude of the ocsillating current in resonance spin flipper according to the flight time of neutrons.

多层自旋分离器（MSS）是由磁反射镜、间隙层和非磁反射镜组成的多层结构。当一个处于磁平行和反平行分量叠加状态的中子入射到MSS时，由于平行和反平行分量被不同的层反射，两个自旋分量之间引入了相位差。从量子力学的角度来看，这种相位差相当于中子在磁场中的拉莫尔进动角。本研究的目的是用MSS取代中子自旋回波（NSE）仪器中的巨大磁体，开发各种新型自旋回波仪器。本文的研究结果如下：a。为了代替NSE光谱仪中的进动磁场，应将一对MSS组合成（++）的结构，以避免由于光束发散而降低偏振。通过磁控溅射技术，MSS中间隙层的均匀性约为7nm，为NSE光谱仪提供了较低的极化率。相反，真空蒸发技术可以提供足够的层均匀性。我们利用MSS的sd成功地进行了初步的NSE实验，开发了小型共振中子自旋鳍片，并成功地获得了频率高达300kHz的NSE信号。这些小的共振自旋鳍，具有低磁场驱动的偏振镜，使我们能够将NSE仪器与其他光谱仪相结合，如反射计或小角度衍射计。为了将这些仪器应用于散裂中子源，我们构建了根据中子的飞行时间改变共振自旋鳍片振荡电流振幅的系统。