Laboratory arrangement for soft x-ray zone plate efficiency measurements

Investigation of surface topology of printed nanoparticle layers using wide-angle low-Q scattering

A new small-angle scattering technique in reflection geometry is described which enables a topological study of rough surfaces. This is achieved by using long-wavelength soft X-rays which are scattered at wide angles but in the low-Q range normally associated with small-angle scattering. The use of nanometre-wavelength radiation restricts the penetration to a thin surface layer which follows the topology of the surface, while moving the scattered beam to wider angles preventing shadowing by the surface features. The technique is, however, only applicable to rough surfaces for which there is no specular reflection, so that only the scattered beam was detected by the detector. As an example, a study of the surfaces of rough layers of silicon produced by the deposition of nanoparticles by blade-coating is presented. The surfaces of the blade-coated layers have rough features of the order of several micrometers. Using 2 nm and 13 nm X-rays scattered at angular ranges of 5° ≤ θ ≤ 51° and 5° ≤ θ ≤ 45°, respectively, a combined range of scattering vector of 0.00842 Å(-1) ≤ Q ≤ 0.4883 Å(-1) was obtained. Comparison with previous transmission SAXS and USAXS studies of the same materials indicates that the new method does probe the surface topology rather than the internal microstructure.

Nanoimaging cells using soft X-ray tomography

Soft X-ray microscopy is ideally suited to visualizing and quantifying biological cells. Specimens, including eukaryotic cells, are imaged intact, unstained and fully hydrated, and therefore visualized in a near-native state. The contrast in soft X-ray microscopy is generated by the differential attenuation of X-rays by the molecules in the specimen-water is relatively transmissive to this type of illumination compared to carbon and nitrogen. The attenuation of X-rays by the specimen follows the Beer-Lambert law, and therefore both linear and a quantitative measure of thickness and chemical species present at each point in the cell. In this chapter, we will describe the procedures and computational methods that lead to 50 nm (or better) tomographic reconstructions of cells using soft X-ray microscope data, and the subsequent segmentation and analysis of these volumetric reconstructions. In addition to being a high-fidelity imaging modality, soft X-ray tomography is relatively high-throughput; a complete tomographic data set can be collected in a matter of minutes. This new modality is being applied to imaging cells that range from small prokaryotes to stem cells obtained from mammalian tissues.

High-efficiency Fresnel zone plates for hard X-rays by 100 keV e-beam lithography and electroplating

The fabrication and characterization of Fresnel zone plates (FZPs) for hard X-ray microscopy applications are reported. High-quality 500 nm- and 1 µm-thick Au FZPs with outermost zone widths down to 50 nm and 70 nm, respectively, and with diameters up to 600 µm were fabricated. The diffraction efficiencies of the fabricated FZPs were measured for a wide range of X-ray energies (2.8-13.2 keV) showing excellent values up to 65-75% of the theoretical values, reflecting the good quality of the FZPs. Spatially resolved diffraction efficiency measurements indicate the uniformity of the FZPs and a defect-free structure.