SKM 2021 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 5: Poster Session KFM

KFM 5.23: Poster

Dienstag, 28. September 2021, 16:00–17:00, P

Nested mirror systems for neutron extraction, transport and focusing — •Christoph Herb¹, Oliver Zimmer², Robert Georgii^{1, 3}, and Peter Böni¹ — ¹Physics Department E21, Technical University Munich, 85748 Garching, Germany — ²Institute Laue-Langevin, F-38042 Grenoble, France — ³Heinz Maier-Leibnitz Zentrum, Technical University Munich, 85748 Garching, Germnay

The investigation of small samples by neutron scattering is usually very time consuming due to the low neutron flux of contemporary sources and small signals from the sample. Elliptic neutron guides are used to transport neutrons over large distances to make room for additional beamlines and for improving the signal-to-noise ratio by focusing the available neutrons onto the sample. However, elliptic guides do not image objects properly due to coma aberrations. We propose using nested arrays of short elliptic mirrors to reduce the coma aberrations.

We report on the investigation of a nested mirror optic at the MIRA beamline. The key properties of the optic are a large brilliance transfer of approximately 72% and the possibility of adjusting the beam size and the divergence of the neutron beam at the sample position by apertures placed before the nested mirror optic. Therefore, no beam shaping devices are required close to the sample position, thus reducing the background.

Nested mirrors will also be particularly useful for the efficient extraction of neutrons from small, highly brilliant moderators such as at the ESS, since common illumination losses associated with using neutron guides are mitigated.