Short focal length Kirkpatrick-Baez mirrors for a hard x-ray nanoprobe

Abstract

We describe progress in the fabrication of short-focal-length total-external-reflection Kirkpatrick-Baez x-ray mirrors with ultralow figure errors. The short focal length optics produce nanoscale beams (<100nm) on conventional (∼64m long) beamlines at third generation synchrotron sources. The total-external reflection optics are inherently achromatic and efficiently focus a white (polychromatic) or a tunable monochromatic spectrum of x rays. The ability to focus independent of wavelength allows novel new experimental capabilities. Mirrors have been fabricated both by computer assisted profiling (differential polishing) and by profile coating (coating through a mask onto ultra-smooth surfaces). A doubly focused 85×95nm2 hard x-ray nanobeam has been obtained on the UNICAT beamline 34-ID at the Advanced Photon Source. The performance of the mirrors, techniques for characterizing the spot size, and factors limiting focusing performance are discussed.

X-ray micro-beam characterization of lattice rotations and distortions due to an individual dislocation

“…However, for beam sizes 425 nm and measurement depths of a few microns, this is likely to be a minor effect. Sub 200 nm achromatic focussing has already been demonstrated 43 , indeed the record for the smallest hard X-ray focal spot size obtained using achromatic Kirkpatrick-Baez mirrors is currently 25 nm 44 . Incorporating these focussing optics into m-Laue instruments and refining the DAXM technique for sub 200 nm resolution will pose significant technical challenges, particularly in terms of optics and long-term stability.…”

Correcting lateral chromatic aberrations in non-monochromatic X-ray microscopy

“…4 More recently, microscopy based on Kirkpatrick-Baez mirrors was performed, showing negligible chromatic aberration in the 8-11 keV range, making the technique suitable for spectromicroscopy. 5 Focusing X-ray optics is commonly based either on curved crystal mirrors, [6][7][8] Fresnel zone plates, 9 or compound refractive lenses (CRLs). 10 Using CRLs for microscopy has the advantage of high efficiency, and scalability to higher energy x-rays, 11 which is beneficial when sample transmission is a limiting factor.…”

Achromatic nested Kirkpatrick–Baez mirror optics for hard X-ray nanofocusing

“…Each stripe is equivalent to a $ 20 nm-wide pseudo-slit or reflector. Either Au fluorescence or the reflected intensity by film was collected (Liu et al, 2005). The patterned multiple nanoslits/ reflectors can profile the beam at 200 mm increments along the beam axis, so that the focal point can be quickly located and precisely measured.…”

“…A horizontal slit at 28 m was placed to control the total power in the beam and to reduce the horizontal source size down to < 100 mm; thus it also acts as a new effective object. In the vertical plane the APS type-A undulator source, with FWHM of about 40 mm, serves directly as the object (Liu et al, 2005).…”