Preparation and characteristic study of nanometer thickness depleted uranium / Au multilayer

Abstract

Modeling and experimental results show that the depleted uranium (DU) and Aucocktail nanometer multilayer will improve the X-ray conversion efficiency by reducing energy loss to penetration of the X-ray into the hohlraum wall. DU/Au multilayer plane film is deposited by magnetron sputtering through alternately rotating substrate in front of separate DU and Au sources. The geometry parameter, surface topography, atomic concentration and interface structure of DU/Au multilayer are characterized by white light interferometer, scanning electronic microscope (SEM) and X-ray photoelectron spectroscopy (XPS). Au film becomes continuous when its thickness reaches 8 nm. Combining with theoretical modeling results, 30 nm DU and 8 nm Au multilayer is chosen. The periodic thickness of DU/Au is measured to be about 37 nm. Well-defined Du/Au interface is observed by SEM. Diffusion at DU/Au interface is observed by XPS. The atomic concentration ratio of DU, Au, O is 73:26:1. The binding energy of Au 4f of 8 nm thickness Au film shifts toward high-energy tail about by 0.6 eV. Similar phenomena are unfound in 30 nm thickness DU film.