Neutron time-of-flight spectroscopy

The time-of-flight technique is employed in two of the instruments at the NIST Cold Neutron Research Facility (CNRF).A pulsed monochromatic beam strikes the sample, and the energies of scattered neutrons are determined from their timesof-flight to an array of detectors.The timeof-flight method may be used in a variety of types of experiments such as studies of vibrational and magnetic excitations, tunneling spectroscopy, and quasielastic scattering studies of diffusional behavior; several examples of experiments are dis-cussed.We also present brief descriptions of the CNRF time-of-flight instruments, including their modi operandi and some of their more pertinent parameters and performance characteristics.