Everything SAXS

Beamtime and Sample Preparation Guide

Preparing well for a beamtime will make your experiment successful and life much easier. Here is a guide for preparing for beamtimes, as well as the techniques we use for preparing samples inside of capillaries.

Fitting Data Using SasView

We use the SasView fitting software to fit small angle scattering data. It is free software that can be downloaded at https://www.sasview.org/. This PDF will take you through fitting your SAXS data to models in SasView.

The software changes as new versions are released, therefore it is important to note which version of the software you use to fit a set of data as new versions may change the fitting. This guide is for SasView version 5.0.3. When in the software, the version you are using can be found by going to “Help” and then “About”.

To fit your 1D processed data, you need to know your scattering length density (SLD). This can be calculated online using the NIST SLD calculator (https://www.ncnr.nist.gov/resources/activation/). For our short peptides, we generally assume a density of 1.55 g/cm³ when calculating the SLD.

Data Retrieval from Diamond Light Source and Processing Data Using DAWN

This guide will guide you through how to access and download raw SAXS data after a beamtime at Diamond Light Source and how to perform background subtraction using DAWN 2.27 on your raw data files.

Scattering Tutorials and Simulations

For quick tutorials on everything scattering-related: https://sastutorials.org/

Shape2SAS calculates the 1D small angle scattering from a predefined structure given by the user. https://bayesfit.genapp.rocks/shape2sas/

Extra Information

Background on the theory of small angle scattering and how we use it for our materials. https://doi.org/10.1039/d1sm01707a

Here are some useful resources from Dr Brian Pauw for more detailed information on everything SAXS-related.

Blog: https://lookingatnothing.com/index.php/about

YouTube: https://www.youtube.com/user/drheaddamage