New generation high performance in situ polarized 3He system for time-of-flight beam at spallation sources

C Y Jiang; X Tong; D R Brown; A Glavic; H Ambaye; R Goyette; M Hoffmann; A A Parizzi; L Robertson; V Lauter

doi:10.1063/1.4975991

New generation high performance in situ polarized ³He system for time-of-flight beam at spallation sources

Rev Sci Instrum. 2017 Feb;88(2):025111. doi: 10.1063/1.4975991.

Authors

C Y Jiang¹, X Tong¹, D R Brown¹, A Glavic², H Ambaye¹, R Goyette¹, M Hoffmann¹, A A Parizzi¹, L Robertson¹, V Lauter²

Affiliations

¹ Instrument and Source Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.
² Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, USA.

PMID: 28249509
DOI: 10.1063/1.4975991

Abstract

Modern spallation neutron sources generate high intensity neutron beams with a broad wavelength band applied to exploring new nano- and meso-scale materials from a few atomic monolayers thick to complicated prototype device-like systems with multiple buried interfaces. The availability of high performance neutron polarizers and analyzers in neutron scattering experiments is vital for understanding magnetism in systems with novel functionalities. We report the development of a new generation of the in situ polarized ³He neutron polarization analyzer for the Magnetism Reflectometer at the Spallation Neutron Source at Oak Ridge National Laboratory. With a new optical layout and laser system, the ³He polarization reached and maintained 84% as compared to 76% in the first-generation system. The polarization improvement allows achieving the transmission function varying from 50% to 15% for the polarized neutron beam with the wavelength band of 2-9 Angstroms. This achievement brings a new class of experiments with optimal performance in sensitivity to very small magnetic moments in nano systems and opens up the horizon for its applications.