Spin-analyzed SANS for soft matter applications

Polarization analysis for small-angle neutron scattering with a 3He spin filter at a pulsed neutron source

“…In this work, we discuss the issue of whether our NPA technique is capable of correctly removing the effect of inelastic incoherent neutron scattering in I coh (Q). Moreover, it is known that the effect of multiple neutron scattering also obscures I coh (Q) in NPA (Chen et al, 2017). We show that the accurate evaluation of I inc (Q) with consideration of the multiple neutron scattering during NPA enables us to provide an authentic I coh (Q).…”

“…Neutron spin filters using polarized 3 He gas, which are referred to as 3 He spin filters (Coulter et al, 1988), are anticipated to be powerful devices for performing NPA in SANS experiments involving pulsed neutron sources. Since the first application of a 3 He spin filter to NPA in a SANS experiment using a monochromatic neutron beam at the National Institute of Standards and Technology (NIST) Center for Neutron Research (Gentile et al, 2000), 3 He spin filters have been widely used to polarize neutron beams and analyze neutron spin polarity (Babcock et al, 2016;Beecham et al, 2011;Chen et al, 2017;Dhiman et al, 2017;Lee & D'Adam, 2016;Leliè vre-Berna, 2007). Polarized 3 He gas has a quite different absorption cross sections for neutrons with parallel and antiparallel spin polarity relative to the nuclear spin of the 3 He(n, p) 3 H reaction (Passell & Schermer, 1966).…”

The high-intensity option of the SANS diffractometer KWS-2 at JCNS – characterization and performance of the new multi-megahertz detection system

“…This is a very special correction which, for an unambiguous characterization of the protein morphology, would require measurements using polarized neutrons and polarization analysis. In this way the incoherent free signals from the protein buffer solution and from the buffer solution can be acquired separately from the Q-independent incoherent background (Salhi et al, 2017;Chen et al, 2017). The use of a 3 He spin analyser, as is planned to be used in the near future on KWS-2, should take care of a proper treatment of the inelastic scattering from protonated components in the sample, as reported by Chen et al (2017).…”

“…In this way the incoherent free signals from the protein buffer solution and from the buffer solution can be acquired separately from the Q-independent incoherent background (Salhi et al, 2017;Chen et al, 2017). The use of a 3 He spin analyser, as is planned to be used in the near future on KWS-2, should take care of a proper treatment of the inelastic scattering from protonated components in the sample, as reported by Chen et al (2017). The inelastic scattering effects occurring in the case of incoherently scattering systems, such as biological macromolecules in a partially or fully protonated buffer solution which achieves special contrast-matching conditions and a physiological state of the system, induce a shift in neutron energy from longer to shorter wavelengths (Ghosh & Rennie, 1990;Rennie & Heenan, 1993;Do et al, 2014).…”

“…Thus, the inelastic scattering from hydrogenated materials makes separation of the coherent and incoherent scattering by the usual SANS polarization analysis method incorrect. The use of TOF data acquisition for the correct interpretation of elastically scattered data is necessary when using spin analysis for the separation of the coherent signal from incoherent background for soft-matter and biological systems (Chen et al, 2017). Although KWS-2 is not a dedicated TOF instrument, the inelastic scattering from highly protonated samples could be observed in special cases using the TOF data-acquisition mode for long detection distances and with long neutron wavelengths ( Fig.…”