Efficient sub 100 nm focusing of hard x rays

An x-ray beam with energy of 20.5 keV has been efficiently focused down to a spot size as small as 90 nm390 nm by a Kirkpatrick–Baez reflecting mirrors device. The first mirror, coated with a graded multilayer, plays both the role of vertical focusing device and monochromator, resulting in a very high flux s231011 photons/sd and medium monochromaticity sDE /E,10−2d. Evaluation of the error contributions shows that the vertical focus is presently limited by the mirror figure errors, while the horizontal focus is limited by the horizontal extension of the x-ray source. With a gain in excess of a few million, this device opens up new possibilities in trace element nanoanalysis and fast projection microscopy. © 2005 American Institute of Physics. fDOI: 10.1063/1.1928191g