Tutorial: Polydispersity

Tutorial contributors: Andreas Haahr Larsen.

Polydispers silica nanoparticles (NP). Reprinted from Pauw et al., 2023, with permission.

Before you start

  • Download and install SasView (on MacOS: you need to install Xcode first).
  • Download and install McSAS.
  • Basic knowledge of fitting in SasView with inclusion of polydispersity is assumed, e.g. from the Spheres tutorial.

Learning outcomes

Learn to analyse polydisperse samples with SAXS, including normal distributions, multimoldal size distributions, or free-form distributions.
  • Model size distributions in SasView, including multimodal size distributions.
  • Model free-form size distribution in McSAS.

Introductory remarks

Many samples are highly polydisperse, i.e. they contain particles that vary in size. This distribution of sizes may be described by a size distribution in one or more structural. The simplest case is a sample of spheres, with a normal distributed polydispersity in their radius, as discussed in the Spheres tutorial. However, here you will deal with more complex size distributions, with focus on the use of McSAS, a software package for extracting free-form size disriutions from SAXS (or SANS) data.

Part I: Polydispersity in SasView

coming august 2024...

Part II: Free from size distribution (McSAS)

coming august 2024...

Part 3: Multimodal size distribution (SasView/McSAS)

coming august 2024...


  1. coming...