Anomalous expansion of tungsten‐carbon multilayers used in x‐ray optics

Using microcleavage transmission electron microscopy and x‐ray diffraction, we have studied the anomalous expansion observed in tungsten‐carbon multilayers. Our results show that the expansion is mostly due to an agglomeration of the tungsten and the effect is larger for samples that have a thinner tungsten layer. Implications for soft x‐ray optics are discussed.