Abstract
To study and control the incoherent inelastic background in small-angle neutron scattering, which makes a significant contribution to the detected scattering from hydrocarbon systems, the KWS-2 small-angle neutron scattering diffractometer operated by the Jülich Centre for Neutron Science (JCNS) at Heinz-Maier Leibnitz Zentrum (MLZ), Garching, Germany, was equipped with a secondary single-disc chopper that is placed in front of the sample stage. This makes it possible to record in time-of-flight mode the scattered neutrons in the high-Q regime of the instrument (i.e. short incoming wavelengths and detection distances) and to discard the inelastic component from the measured data. Examples of measurements on different materials routinely used as standard samples, sample containers and solvents in the experiments at KWS-2 are presented. When only the elastic region of the spectrum is used in the data-reduction procedure, a decrease of up to two times in the incoherent background of the experimentally measured scattering cross section may be obtained. The proof of principle is demonstrated on a solution of bovine serum albumin in D2O.
Highlights
In a small-angle neutron scattering (SANS) experiment one measures the coherent scattering, which bears structural information about the sample and is predominantly elastic, and the Q-independent incoherent scattering
We report here on the testing of different materials used in SANS experiments in different relevant conditions for routine measurements at KWS-2
TOF measurements of the scattering from different materials commonly used in SANS experiments at KWS-2, i.e. standard samples [Plexiglas, glassy carbon (GC), silver behenate AgBeh], sample containers and solvents (H2O, D2O), were carried out with i = 5 and 7 Aat LD = 1.1 and 1.6 m
Summary
In a small-angle neutron scattering (SANS) experiment one measures the coherent scattering, which bears structural information about the sample and is predominantly elastic, and the Q-independent incoherent scattering. We discuss what one can learn at KWS-2 in a quick manner, during the experiment, about the incoherent inelastic background from soft-matter and biological samples, and how one can collect data with reduced incoherent background, on demand This new option will pave the way for a more accurate detection of weak scattering signals from small structures, e.g. from small proteins or short polymer chains in solution, when combined with the wideangle detection option, for reaching Qmax = 2 A À1, and with the polarization-analysis option using spin-exchange optical pumping (SEOP) polarized 3He neutron-spin filters (Salhi et al, 2017), which are currently in development at KWS-2
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
