Crystal monochromator

A crystal monochromator is a device in neutron and X-ray optics to select a defined wavelength of the radiation for further purpose on a dedicated instrument or beamline.

Similar devices are called crystal analyzer for the examination of scattered radiation.

It operates based on the principle of diffraction through a crystalline structure, governed by Bragg's Law.

Crystal monochromators are integral to applications in materials science, structural biology, and high-energy physics.

The diffraction condition is defined by Bragg’s Law: nλ=2dsinθ Where: By adjusting the angle of the crystal, the monochromator selectively allows radiation of a desired wavelength to pass while filtering out others.

Neutron monochromator for the ECHIDNA powder diffractometer at OPAL in Australia. It is made by slabs of [113] oriented Germanium crystals which are inclined towards each other in order to focus down the Bragg reflected beam.