Reflectivity measurement inside small hollow mirrors using an x-ray tube

Abstract

Small hollow x-ray mirrors are manufactured by several techniques. The mirror material—the reflecting surface itself—can be either a simple metal, such as Au or Ni, or a multilayer. The development of a manufacturing technique, however, requires a simple way of measuring the mirror reflectivity curves. This may be done using a pencil beam at the synchrotron, but it is rather difficult to make it in a laboratory using an x-ray tube. This paper describes the development of a method of carrying out absolute reflectivity measurements inside these mirrors using only a typical laboratory source. Thus, we provide a fast, convenient and inexpensive way to perform mirror characterization. The method was tested in a laboratory and verified in synchrotron experiments in the case of conical micromirrors, while tests for other mirror shapes are under way. The method utilizes only an x-ray tube, an x-ray camera and linear motorized stages. The tube and the camera are moving relative to the mirror in a predefined way taking images of the peak. Detected images are then automatically processed in order to obtain a reflectivity curve. A fully automatic measurement including automatic focusing is also possible and is under development. A typical manual measurement takes approximately 1–2 h for one reflectivity curve at present.