How it works

Simulated experiment

• The polychromatic beam from the hot neutron tube H3 arrives at the monochromator.
• The monochromatic diffracted beam reaches the sample – a single crystal - located at the centre of the Eulerian cradle.
• The three angles of the Eulerian cradle are rotated so as to set the sample in the required orientation, for diffraction to occur.
• The 2D position sensitive detector is rotated to the calculated position for the selected Bragg reflections.
• The sample is rotated step by step around the vertical axis while the detector records the intensity of the diffracted beam of the selected Bragg reflection.

When the intensities of a large enough number – typically 1000 to 20000 - of Bragg reflections have been collected, they can be used to compute the crystal structure of the sample i.e. to determine the position and nature of its atoms.