X-ray diffraction patterns consist of a number of Bragg-reflections,
which in common are individually broadened. This broadening is caused by
three reasons:
- the finite width of the wavelength distribution of the X-ray source
- the broadening due to geometrical conditions of the instrument
- the broadening due to size and microstrain effects in the sample
BGMN separates the first two topics from the Rietveld refinement. The
wavelength distribution is predetermined (as file) and for a given device
setup an instrumental geometric profile has to be calculated once.
BGMN enables two different sources for the geometric part:
- Raytraced
Profiles. In general, we recommend this profiles whenever they
are possible. However, there are special geometric diffractometer set-ups
(e.g. Multilayer Mirrors, PSD's etc.) for which raytracing is impossible
due to manufacturing tolerances. In such cases, we recommend
- Learnt Profiles
as an alternative way.
Both ways uses identic mathematic profile description. The main difference:
For raytraced profiles, no measuring or an half hour tube tails measurement
is needed. Learnt profiles demand for a multiple day standard measurement.
