Neuwirth Tobias, Backs Alexander, Gustschin Alex, Vogt Simon, Pfeiffer Franz, Böni Peter, Schulz Michael
Technical University of Munich, Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748, Garching, Germany.
Technical University of Munich, Department of Physics, Chair for Neutron Scattering (E21), James-Franck-Str. 1, 85748, Garching, Germany.
Sci Rep. 2020 Feb 4;10(1):1764. doi: 10.1038/s41598-020-58504-7.
Neutron grating interferometry (nGI) is a unique technique allowing to probe magnetic and nuclear properties of materials not accessible in standard neutron imaging. The signal-to-noise ratio of an nGI setup is strongly dependent on the achievable visibility. Hence, for analysis of weak signals or short measurement times a high visibility is desired. We developed a new Talbot-Lau interferometer using the third Talbot order with an unprecedented visibility (0.74) over a large field of view. Using the third Talbot order and the resulting decreased asymmetry allows to access a wide correlation length range. Moreover, we have used a novel technique for the production of the absorption gratings which provides nearly binary gratings even for thermal neutrons. The performance of the new interferometer is demonstrated by visualizing the local magnetic domain wall density in electrical steel sheets when influenced by residual stress induced by embossing. We demonstrate that it is possible to affect the density of the magnetic domain walls by embossing and therefore to engineer the guiding of magnetic fields in electrical steel sheets. The excellent performance of our new setup will also facilitate future studies of dynamic effects in electric steels and other systems.
中子光栅干涉测量术（nGI）是一种独特的技术，能够探测标准中子成像中无法获取的材料的磁性和核特性。nGI装置的信噪比强烈依赖于可实现的可见度。因此，对于弱信号分析或短测量时间而言，需要高可见度。我们开发了一种新的塔尔博特 - 劳干涉仪，它使用三阶塔尔博特效应，在大视场上具有前所未有的可见度（0.74）。利用三阶塔尔博特效应以及由此降低的不对称性，可以获得较宽的相关长度范围。此外，我们采用了一种生产吸收光栅的新技术，即使对于热中子也能提供近乎二元的光栅。通过可视化压花引起的残余应力影响下电工钢片中的局部磁畴壁密度，展示了新型干涉仪的性能。我们证明，通过压花可以影响磁畴壁的密度，从而设计电工钢片中磁场的引导。我们新装置的卓越性能也将促进未来对电工钢和其他系统中动态效应的研究。
