Tutorial SANS Application

This short tutorial shows how to load the bundled SANS examples, inspect the standard scattering views, and create a simple Debye theory calculation.

Load SANS Data

1. Start RepTate and create a new SANS application.

2. Open the example files in data/PS_SANS:

   • 100k.sans

   • 250k.sans

   • 400k.sans

   The SANS application reads text files with the .sans extension. Each file should contain the molecular weight Mw and deuterated-chain volume fraction phi (or Phi) as file parameters, followed by columns for the scattering vector q and intensity I(q).

Inspect Views

Use the View selector to switch between the SANS representations:

• log(I(q)) plots log10(q) against log10(abs(I(q))).

• I(q) plots the measured intensity as a function of scattering vector.

• Zimm plots 1/I(q) against q^2.

• Kratky plots q^2 I(q) against q.

Add a Debye Theory

1. In the theory selector, choose Debye and create the theory.

2. Click Calculate to evaluate the Debye function for the loaded files. The theory uses Mw and phi/Phi from each file and the theory parameters Contrast, C_gyr, M_mono, and Bckgrnd.

3. Use Minimize Error only when you want to fit the adjustable parameters. The optional Stretched and Non-Ideal Mix buttons enable the corresponding lambda and chi terms described in the Debye theory documentation.