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RAINBOWS: refractive analysis of the incoming neutron beam over the white spectrum. A new fast neutron reflectometry technique exploiting a focusing prism
Author(s) -
Cubitt Robert,
Segura Ruiz Jaime,
Jark Werner
Publication year - 2018
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576718001528
Subject(s) - optics , prism , neutron , neutron reflectometry , neutron radiation , wavelength , reflectometry , beam (structure) , refraction , physics , materials science , neutron scattering , small angle neutron scattering , scattering , nuclear physics , computer science , time domain , computer vision
Neutron reflectivity is a powerful technique for characterizing interfaces in many areas of science. The traditional method of time of flight for measuring the wavelength of neutrons in a white beam is extremely wasteful, as the vast majority of neutrons must be absorbed in the choppers in order to produce a pulsed beam. A prism operates continuously, with a transmission up to two orders of magnitude higher than choppers. The wavelength‐dependent deflection of the beam by the prism, coupled with a high spatial resolution detector, results in excellent wavelength resolution. The theory of how the resolution is considerably enhanced by curving the surface of the prism is described in detail for a real experimental arrangement. It is demonstrated how this can be used for faster neutron reflectometry, including the merging of different angles and subtraction of background. The technique shows considerable promise for neutron reflectivity, opening up new areas of science particularly in the realms of kinetics and small samples.