Simulated experiment
- A polychromatic (white), neutron beam is partially monochromatised by the two counter-rotating disc choppers, generating a packet of neutrons which then falls upon the monochromator. This is set at an incident angle selected to define the desired neutron wavelength by Bragg’s Law.
- The reflected monochromatic beam then passes to the Fermi chopper, effectively a rotating collimator, which only transmits neutrons when the neutron path is parallel to the slits. This produces very short neutron bites from the monochromatic packets, which are then detected by time-of-flight, with the flightpath being the distance between the Fermi chopper and the detectors.
- Both the neutron energy gain/loss and the angle through which the neutrons are scattered are analysed, yielding information on both the dynamical and structural aspects of the sample scattering function.
