Some neutron diffraction experiments on curved silicon crystals

The diffraction properties of curved silicon crystals, with curvature radii between ∞ and 25 m obtained by microscopic techniques, were investigated by means of a neutron diffractometer. The ratio of neutron reflectivity between plane and curved silicon crystals was measured as a function of the neutron wavelength using different reflecting planes in both Bragg and Laue cases in symmetrical and asymmetrical conditions. The experimental results were interpreted with the results of theoretical investigations on the dynamical theory of diffraction applied to the curved-crystal case. The implications of this work on neutron monochromator design are briefly discussed.