can often be interpreted in the same way as spectra obtained by conventional spectroscopic techniques; insofar as inelastic neutron scattering can be seen as a special spectroscopy. Inelastic scattering experiments normally require a monochromatization of the incident or outgoing beam and an energy analysis of the scattered neutrons. This can be done either through time-of-flight techniques (neutron time-of-flight scattering) or through Bragg reflection from single crystals (neutron triple-axis spectroscopy, neutron backscattering). Monochromatization is not needed in echo techniques (neutron spin echo, neutron resonance spin echo), which use the quantum mechanical phase of the neutrons in addition to their amplitudes. History The first neutron diffraction experiments were performed in the 1930s. However it was not until around 1945, with the advent of nuclear reactors, that high neutron fluxes became possible, leading to the possibility of in-depth structure investigations. The first neutron-scattering instruments were installed in beam tubes at multi-purpose research reactors. In the 1960s, high-flux reactors were built that were optimized for beam-tube experiments. The development culminated in the high-flux reactor of the Institut Laue-Langevin (in operation since 1972) that achieved the highest neutron flux to this date. Besides a few high-flux sources, there were some twenty medium-flux reactor sources at universities and other research institutes. Starting in the 1980s, many of these medium-flux sources were shut down, and research concentrated at a few world-leading high-flux sources. Facilities Today, most neutron scattering experiments are performed by research scientists who apply for beamtime at neutron sources through a formal proposal procedure. Because of the low count rates involved in neutron scattering experiments, relatively long periods of beam time (on the order of days) are usually required for usable data sets. Proposals are assessed for feasibility and scientific interest. Techniques Neutron diffraction Small angle neutron scattering Spin Echo Small angle neutron scattering Neutron reflectometry Inelastic neutron scattering Neutron triple-axis spectrometry Neutron time-of-flight scattering Neutron backscattering Neutron spin echo See also Neutron transport LARMOR neutron microscope Born approximation References External links Free, EU-sponsored e-learning resource for neutron scattering Neutron scattering - a case study Neutron Scattering - A primer (LANL-hosted black-and-white version) - An introductory article written by Roger Pynn (Los Alamos National Laboratory) Podcast Interview with two ILL scientists about neutron science/scattering at the ILL YouTube video explaining the activities of the Jülich Centre for Neutron Scattering Neutronsources.org Science and Innovation with Neutrons in Europe in 2020 (SINE2020) IAEA neutron beam instrument database