- The soller slits reduce the axial divergence of the X-Ray beam to less than 6° (in some instruments even 4° or even 2°). Reducing the axial divergence will reduce the peak asymmetry in the output.
- The divergence slit reduces the height divergence (beam spread). This narrows the peaks and increases the resolution of the output.
- The monochromator(s) (only available in some models), is usually a filter which absorbs most of the Kβ radiation and the white radiation. Only Kα1 and Kα2 radiation are allowed to pass through. Note: High resolution diffractometers use a single crystal monochromator right after the X-ray source. In this case only monochromatic Kα1 radiation is allowed to pass through.
Images taken from the NTU XRD site page