Focusing of X-rays by Total External Reflection from a Paraboloidally Tapered Glass Capillary

The first observation of a true geometrical focus of X-rays well beyond the exit of a paraboloidally tapered glass monocapillary is reported. An intensity gain of 250 ± 20 into a 6 × 9 μm pinhole for 8 keV X-rays and transmission efficiencies of more than 90% below 20 keV were observed.