Temperature-dependent thermal properties of Ru/C multilayers

: Multilayers made of Ru/C are the most promising candidates when working in the energy region 8-20 keV. The stability of its thermal properties, including thermal expansion and thermal conduction, needs to be considered for monochromator or focusing components. Ru/C multilayers with periodic thicknesses of 3, 4 and 5 nm were investigated in situ by grazing-incidence X-ray reflectometry and diffuse scattering in order to study their thermal expansion characteristics as a function of annealing temperature up to 400°C. The thermal conductivity of multilayers with the same structure was also measured by the transient hot-wire method and compared with bulk values.