Neutron time-of-flight scattering

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In Neutron time-of-flight scattering, a form of inelastic neutron scattering, the initial position and velocity of a pulse of neutrons is fixed, and their final position and the time after the pulse that the neutrons are detected are measured. By the principle of conservation of momentum, these pairs of coordinates may be transformed into momenta and energies for the neutrons, and the experimentalist may use this information to calculate the momentum and energy transferred to the sample. Inverse geometry spectrometers are also possible. In this case, the final position and velocity are fixed, and the incident coordinates varied.

Time-of-flight scattering can be performed at either a research reactor or a spallation source.

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Existing time-of-flight spectrometers at spallation sources:

• LRMECS and HRMECS at Argonne National Laboratory
• Pharos at LANSCE's Lujan Center at Los Alamos National Laboratory
• MAPS, MARI, HET at the ISIS neutron source

Soon to be time-of-flight spectrometers at spallation sources:

• ARCS , CNCS, and SEQUOIA at the Spallation Neutron Source
• MERLIN and LET at the ISIS neutron source

Existing time-of-flight spectrometers at research reactors:

• DCS and FCS at the NIST laboratories in Maryland.
• IN4, IN5, and IN6 at the Institut Laue-Langevin
• TOFTOF at the Forschungsneutronenquelle Heinz Maier-Leibnitz

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