Effects of Multiple Scattering Encountered for Various Small-Angle Scattering Model Functions

Published

October 1, 2018

Author(s)

Grethe Vestergaard Jensen, John Barker

Abstract

In small-angle scattering (SAS) theory and data modeling, it is generally assumed that each scattered ray - photon or neutron - is only scattered one time on its path through the sample. This assumption greatly simplifies the interpretation of the data, and is valid in many cases. However, it breaks down under conditions of high scattering power, increasing with sample concentration, scattering contrast, sample path length, and ray wavelength. For samples with a significant scattering power, disregarding multiple scattering effects can lead to erroneous conclusions on the structure power, disregarding multiple scattering effects can lead to erroneous conclusions on the structure of the investigated sample. In this paper, multiple scattering effects on different types of scattering patterns are determined and methods for assessing and addressing them are discussed, including the general implementation of multiple scattering effects in structural model fits. The modification by multiple scattering of scattering patterns is determined for the sphere scattering function (Rayleigh, 1910), as well as for Gaussian (Guinier & Fournet, 1955), Debye-Andersen-Brumberger (DAB) (Debye et al., 1957), Sabine (Sabine & Bertram, 1999), and Lorentzian scattering functions, and checked with Monte Carlo simulations. The results show how difference in shape of the scattering function at high q results in different multiple scattering effects at low q, where information on the particle mass and radius of gyration is contained.

Citation

Journal of Applied Crystallography

Volume

51

Issue

5

Pub Type

Journals

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Keywords

small-angle scattering, multiple scattering, data modeling

Citation

, G. and Barker, J. (2018), Effects of Multiple Scattering Encountered for Various Small-Angle Scattering Model Functions, Journal of Applied Crystallography, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=925309 (Accessed April 20, 2024)