Formation of microbeam using tabletop soft X-ray laser

An X-ray microprobe with a sub-micron size beam and high intensity can provide X-ray analyses with a remarkable spatial resolution. We have performed focusing of an X-ray laser output into a sub-micron beam for the first time. In our experiment, an X-ray laser of Li-like Al 3d-4f transition at 15.47 nm was delivered from an unstable cavity consisting of a concave mirror and a flat mirror with a square orifice of 100x100 mu m in size. The beam from the orifice was then focused by using a Schwarzschild mirror coated with a Mo/Si multilayer. An X-ray beam size with a diameter of about 0.45 mu m and an estimated photon number of about 2x10(6) photons per shot was achieved. Such sources could be well suited for the realization of X-ray microprobes. (C) 1999 Elsevier Science B.V. All rights reserved.