Correction of Spherical Aberration in Grazing‐Incidence X‐ray Optics by Combination of Spherical‐Concave Mirrors

摘要

In grazing‐incidence total‐reflection mirror optics for x‐rays, spherical aberrations and coma are the most serious aberrations for microfocusing and microimaging. High‐resolution imaging is believed to be possible only when an aspherical mirror system is used. However, the spherical aberrations of a spherical‐concave mirror in a grazing‐incidence condition can be eliminated by sequential reflection of spherical mirrors of similar shapes. A sub‐micrometer one‐dimensional focusing is easily achieved by the spherical‐aberration‐corrected tandem‐spherical mirror optics. By configuring four spherical mirrors in an analogy of the crossed mirror optics (Kirkpatrick‐Baez optics), it is possible to achieve sub‐micrometer focused beam size in the hard x‐ray region. Preliminary experiments on x‐ray microfocusing have been carried out at beamline 20XU of SPring‐8, and a 0.5?μm×0.4?μm beam size was achieved at 8 keV.