Characterization of sliced multilayer zone plates for hard x rays (invited)

Abstract

Circular zone plates for hard x rays, fabricated by dc planar magnetron sputtering, have been characterized using monochromatized synchroton x rays. The zone plates consisted of either 5 or 20 pairs of altenating WSi2 and C layers. The minimum focal spot size attained was less than 3 μm× 10 μm in the vertical and horizontal directions, respectively. The efficiency of the zone plate with 20 layer pairs was determined to be about 4.5%. An x-ray transmission image of a No. 2000 mesh Cu grid and an x-ray fluorescence image of a patterned Co thin film were measured, and it was demonstrated that a high-resolution image could be obtained with the present zone plate. The possibility of implementing the phase zone plate in hard x-ray range is considered.

Phase transitions and equation of state of CsI under high pressure and the development of a focusing system for x-rays

“…Since only small zone plates of sufficient quality can be made at this time, the intensity in the focused beam is very low. In an earlier report [32) by the same group, the intensity they achieved at the focused spot with 8 ke V monochromatic radiation was only 3x 10 4 photons/s. This is three to four orders of magnitude lower than what is needed for diffraction studies.…”

Hard X-ray focusing by stacked Fresnel zone plates

“…For example, for efficient focusing 30 keV X-rays with gold FZP the required structure thickness is 6 µm and structure around 20 µm is needed to focus 100 keV X-rays. In order to achieve small period and high aspect ratios inherent in lithography technique, the sputtered-sliced FZP method was proposed in 1982 [3][4][5]. Sputtered-sliced FZP have exceptionally high aspect ratio suitable for focusing 100 keV X-rays [5], but the small aperture/acceptance strongly limits applicability of these FZPs.…”

<title>Experimental characterization of Fresnel zone plate for hard x-ray applications</title>

“…this area have utilized microprobes based on multilayer reflective optics2 and transmission amplitude zone plates. 3 We present here the first characterization result of a scanning microscope based on a transmission phase zone plate (ZP) in the hard x-ray region. • Phase ZP is distinct from amplitude ZP in that it has: i) higher focusing efficiency, ii) much lower zeroth order background, iii) less heat load on the ZP.…”