Reduction of the Interfacial Diffusion in Ni-Ti Neutron-Optics Multilayers by Carburation of the Ni-Ti Interfaces

It is shown that it is possible to reduce both interfacial diffusion and interfacial roughness in neutronoptics Ni-Ti multilayered monochromators. This is achieved by the deposition of an ultrathin layer of carbon at the Ni-Ti interfaces. A comparison between treated Ni-Ti multilayers and an untreated one was performed by grazing-angle neutron reflectometry and completed by grazing-angle X-ray reflectometry, Auger electron spectroscopy and secondary-ion mass spectrometry. More specifically, the experimental data show that nickel diffuses into the titanium layers in the untreated multilayers. This diffusion decreases