Contents

How do I get sequential refinements to work in TOPAS 6?

A tutorial for performing sequential refinements can be found at the following link:

Add link to tutorial

Make sure you have commented out the line the defines the "old version" variable.

There is an error in the example file. To fix this, change the line that reads:

macro filename {Filename (Run_Number)}

to

macro filename {File_Name (Run_Number)}

This is getting the value from the File_Name list at index=Run_Number.

A template TOPAS .inp file with additional comments can be downloaded from the link below:

Attach template .inp file with comments

What do the values mean for the PDF peak shape function?

This macro uses multiple cutoffs and a sphere radius for a transition from correlated (low-r) to uncorrelated (high-r) motion.

beqcut is the beq value to be used in the region between 0 and rcut.

beqlo is the beq value to use in the region between rcut and rlo.

beqhi is the beq value for the region r ≥ 2*radius + rlo

The values for dQ, lor and alpha should be refined against a standard with no sample broadening (e.g. Si) and then fixed.