Neutron optics concept for the materials engineering diffractometer at the ESS

6th European Conference on Neutron Scattering

Šaroun, J.^1 ; Fenske, J.^2 ; Rouijaa, M.^2 ; Beran, P.^1 ; Navrátil, J.^1,3 ; Luká, P.^1 ; Schreyer, A.^2 ; Strobl, M.^4

Nuclear Physical Institute, ASCR, Hlavni 130, e

25068, Czech Republic^1

Helmholtz-Zentrum Geesthacht, Max-Planck-Str.1, Geesthacht

21502, Germany^2

Czech Technical University, Faculty of Nuclear Sciences and Physical Engineering, Behová 7, Praha 1

11519, Czech Republic^3

European Spallation Source, Tunavagen 24, Lund

22363, Sweden^4

关键词: European spallation sources;    Focusing optics;    Materials engineering;    Neutron guides;    Neutron transport;    Simulated performance;    Spectral beams;    Wavelength resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/746/1/012011/pdf
DOI  :  10.1088/1742-6596/746/1/012011

来源: IOP

【 摘 要 】

The Beamline for European Materials Engineering Research (BEER) has been recently proposed to be built at the European Spallation Source (ESS). The presented concept of neutron delivery optics for this instrument addresses the problems of bi-spectral beam extraction from a small moderator, optimization of neutron guides profile for long-range neutron transport and focusing at the sample under various constraints. They include free space before and after the guides, a narrow guide section with gaps for choppers, closing of direct line of sight and cost reduction by optimization of the guides cross-section and coating. A system of slits and exchangeable focusing optics is proposed in order to match various wavelength resolution options provided by the pulse shaping and modulation choppers, which permits to efficiently trade resolution for intensity in a wide range. Simulated performance characteristics such as brilliance transfer ratio are complemented by the analysis of the histories of "useful" neutrons obtained by back tracing neutrons hitting the sample, which helps to optimize some of the neutron guide parameters such as supermirror coating.