This is an old revision of the document!
Currently defined fit variables
| Variable | initial lower boundary | Initial upper boundary |
|---|---|---|
| thickness | 0.8*thickness | 1.2*thickness |
| delta | -0.1 | 0.1 |
| beta | 0. | 0.1 |
| sigma | 0. | 20 |
| deltam | -10*deltam | 10*deltam |
| betam | -10*betam | 10*betam |
| angular resolution | 0. | 0.1 |
| measurement multiplicator | 0.1*multiplicator | 10*multiplicator |
| qz translation | -1 | 1 |
| gauss_delta | -10*gauss_delta | 10*gauss_delta |
| gauss_beta | -10*gauss_beta | 10*gauss_beta |
| gauss_variance | 0. | 10*gauss_variance |
| gauss_z | -1 | 1 |
| script variable (par) | 0 | 2 |
Note: The simplex algorithm will not fit variables with an initial value of 0.
Fits of multiple curves at the same time
By activating multiple datasets for fitting it is possible to minimize the Chi^2 error of all curves at the same time with the same set of parameters.
The parameters that can be changed for each measurement curve are the energy, angular resolution, multiplicator, translation and polarization. If the multiplicator is fitted it is used for all fitted curves. Independent fitting of the multiplicator is not possible. If multiple curves should be fitted at the same time the optical constants should not be fitted as they change for each energy. Instead it is recommed that in the tab “Optical Constants Database” the automatically setting of the optical constants from files should be activated. If the optical constants should be fitted as well use the script and script variables.