High Intensity Neutron Beams for Small Samples

1st Conference on Light and Particle Beams in Materials Science 2013

物理学;材料科学

Böni, Peter^1

Physik-Department E21, Technische Universität München, James-Franck-Str. 1, D-85748 Garching, Germany^1

关键词: Focal distances;    Focused beams;    High intensity;    Kirkpatrick-Baez mirror;    Low background;    Novel materials;    Sample environment;    Tapered guides;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/502/1/012047/pdf
DOI  :  10.1088/1742-6596/502/1/012047

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

As novel materials of excellent homogeneity can often only be grown in small quantities it is important to optimize the transport of neutrons from the moderator to the sample while keeping the background low. Using elliptically or parabolically tapered guides the losses can be strongly reduced such that 50%-90% of the useful neutrons arrive at the sample. If not properly designed, however, the divergence at the sample becomes inhomogeneous. In contrast, pairs of nested Kirkpatrick-Baez mirrors in Montel geometry yield well focused beams with a compact phase space. The mirrors extract only the useful neutrons from the moderator and effectively interrupt the line of sight leading to a very low background. As the focal distances are typically several meters, the extraction of the neutrons and the installation of bulky sample environment is facilitated.