Polarization analysis for small‐angle neutron scattering with a 3He spin filter at a pulsed neutron source. Issue 2 (25th March 2021)

• Record Type: Journal Article
• Authors: Okudaira, Takuya; Ueda, Yuki; Hiroi, Kosuke; Motokawa, Ryuhei; Inamura, Yasuhiro; Takata, Shin-ichi; Oku, Takayuki; Suzuki, Jun-ichi; Takahashi, Shingo; Endo, Hitoshi; Iwase, Hiroki
• Is Part Of: Journal of applied crystallography. Volume 54:Issue 2(2021)
• Page Start: 548
• Page End: 556
• Publication Date: 2021-03-25
• Subjects: small‐angle neutron scattering -- SANS -- neutron polarization analysis -- 3He spin filters -- pulsed neutron sources; Crystallography -- Periodicals; 548.05
• DOI: 10.1107/S1600576721001643
• Languages: English
• ISSNs: 0021-8898

Abstract

Abstract : Neutron polarization analysis using a 3 He spin filter for mainly soft matter systems is demonstrated for small‐angle neutron scattering with a pulsed neutron source; successful separation of the coherent scattering component from the incoherent scattering component due to hydrogen atoms was achieved. Abstract : Neutron polarization analysis (NPA) for small‐angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a 3 He spin filter as a spin analyzer for the neutrons scattered from the sample. The cell of the 3 He spin filter gives a weak small‐angle scattering intensity (background) and covers a sufficient solid angle for performing SANS experiments. The relaxation time of the 3 He polarization is sufficient for continuous use for approximately 2 days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to the extremely large incoherent scattering cross section of hydrogen atoms in samples, is difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources such as the Japan Proton Accelerator Research Complex (J‐PARC) and the US Spallation Neutron Source. It is anticipated that this work will contribute significantly to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J‐PARC, particularly for systems involving competition between the coherent and incoherent scattering intensity.