Reflectometry studies of the coherent properties of neutrons

Abstract Thin film is a high resolution neutron interferometer because in it there occur the interference of two waves reflected from two interfaces. If the neutron is characterized by the wave packet with the centre of gravity moving at velocity v , for the incidence on the film at some angle, due to the component of the momentum parallel to the entrance surface the exit point of the neutron on reflection from the back interface shifts along the surface with respect to the entrance point. This shift is depended on the momentum transfer q and analyzing of experimental dependence of the reflectivity R on q it possible to get into the region where a transition from wave to corpuscular properties takes place and thus it allows to estimate the lateral coherence length of the neutron. In this work it makes the lower estimation of the lateral coherence length of the neutron from the time-of-flight reflectometry experiment with copper film on glass substrate and gives comparison with other experimental estimation of this value. (U.Bonse, W.Graeff, H.Rauch, Phys. Lett. 69A, N.6(1979)).