How-To's‎ > ‎Simulation-Modeling‎ > ‎


Peak Analysis Tool

Here we will load two group files, one for the data and another for the resolution. Then, we will apply a user-defined macro in order to fit the data to the following model:
A* Convolution( Resolution(Q,E),  x * Delta(E) + (1-x) * S(Q,E) )
S(Q,E) is the Fourier transform of a stretched exponential.
Note: This fitting takes a long time, faster fitting can be done in Mantid.

Open classic Dave, version 1.3, and then:

Data Analysis --> PAN (peak analysis)

File --> ASCII Files --> Load grouped ascii data

Resolution --> Load grouped ascii resolution function, then Accept on the pop-up window

File --> Preferences, then set the energy domain over which to perform the fit (Lower fit limit = -100 ueV and Upper fit limit = 100 ueV, then Accept, then Dismiss)

In Group selection, select 2 for the second Q-value

In the PAN window, set "groups to fit" to  2-5

Select Function --> User macro function --> Restore Macro, then load the macrofile, then click on Accept.

Modify Fit Parameters pops-up a window to enter values for the initial guess. As a start, let's assume a pure exponential (beta=1 and fixed). Enter the initial guess in the picture below, then Apply and Dismiss.

Click on Fit current group.