Beryllium parabolic refractive x-ray lenses

ABSTRACT Parabolic refractive x-ray lenses are novel optical components for the hard x-ray range from about 5 keV to about120 keV. They focus in both directions. They are compac t, robust, and easy to align and to operate. They can beused like glass lenses are used for visible light, the main dierence being that the numerical aperture NA is muchsmaller than 1 (of order 10 Š 4 to 10 Š 3 ). Their main applications are in micro- and nanofocusing, in imagingby absorption and phase contrast. In combination with tomography they allow for 3-dimensional imaging ofopaque media with sub-micrometer resolution. Finally , they can be used in speckle spectroscopy by means ofcoherent x-ray scattering. Beryllium as lens material strongly enhances the transmission and the “eld of view ascompared to aluminiu m. With increased NA the lateral resolution is also considerably improved with Be lenses.References to a number of applications are given.Keywords: synchrotron radiation, refractive x-ray lenses, beryllium, x-ray imaging, x-ray microscopy, tomog-raphy, x-ray microprobe