Simulation and optimization of a new focusing polarizing bender for the diffuse neutrons scattering spectrometer DNS at MLZ

International Conference on Polarised Neutrons for Condensed Matter Investigations

Nemkovski, K.^1 ; Ioffe, A.^1 ; Su, Y.^1 ; Babcock, E.^1 ; Schweika, W.^2 ; Brückel, Th^2

Jülich Centre for Neutron Science (JCNS), Heinz Maier-Leibnitz-Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, Garching

85748, Germany^1

Jülich Centre for Neutron Science (JCNS), Peter Grünberg Institut (PGI), JARA-FIT, Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, Jülich

524258, Germany^2

关键词: Convergent geometry;    Crystal monochromators;    Different geometry;    Diffuse neutron scatterings;    Neutron transmission;    Polarization efficiencies;    Simulation and optimization;    Simulation packages;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/862/1/012018/pdf
DOI  :  10.1088/1742-6596/862/1/012018

来源: IOP

【 摘 要 】

We present the concept and the results of the simulations of a new polarizer for the diffuse neutron scattering spectrometer DNS at MLZ. The concept of the polarizer is based on the idea of a bender made from the stack of the silicon wafers with a double-side supermirror polarizing coating and absorbing spacers in between. Owing to its compact design, such a system provides more free space for the arrangement of other instrument components. To reduce activation of the polarizer in the high intensity neutron beam of the DNS spectrometer we plan to use the Fe/Si supermirrors instead of currently used FeCoV/Ti:N ones. Using the VITESS simulation package we have performed simulations for horizontally focusing polarizing benders with different geometries in the combination with the double-focusing crystal monochromator of DNS. Neutron transmission and polarization efficiency as well as the effects of the focusing for convergent conventional C-benders and S-benders have been analyzed both for wedge-like and plane-parallel convergent geometries of the channels. The results of these simulations and the advantages/disadvantages of the various configurations are discussed.