[en] The transmission x-ray microscope has so far been used almost exclusively to form images with absorption contrast. Methods of forming phase contrast and darkfield images are considered, particularly in the scanning transmission x-ray microscope, and the advantages and disadvantages of these methods are reviewed, in the context of the new generation of synchrotron x-ray sources that will be able to provide high brightness over a much wider range of energies than is available at present

[en] Avalanche photodiodes (APDs) offer an attractive alternative to the gas flow proportional counter (GFPC) for the counting of individual soft x-ray photons. They are reasonably efficient detectors and have the capability of handling higher count rates than a GFPC. With the advent of intense monochromatic x-ray beams from synchrotron radiation sources, the ability to handle high count rates is becoming more important than the need for any energy resolution. Another attraction of using solid-state detectors is the possibility of multielement fabrication of devices: configured detector arrays can then be considered for a number of applications. For example, in the scanning transmission x-ray microscope such a detector system allows much more sophisticated imaging techniques, such as differential phase contrast imaging with a quadrant APD array. In this paper we compare results for several commercially available APDs used as photon counters with a GFPC over the energy range 200--700 eV. APDs operated in the Geiger mode with a simple passive circuit to quench the avalanche current pulses can achieve count rates of the order of 10⁶ s^-1, and this can be greatly improved upon with the use of an active quenching circuit

[en] The King's College London scanning transmission x-ray microscope in use on beam line 5U2 at the SRS, SERC Daresbury Laboratory, has been modified to allow dark-field images to be formed using only the x rays scattered by the specimen. Experiments have been performed with a number of different detector geometries, and this has confirmed that the strongest scattering arises from edges or thickness gradients in the specimen. Although the dark-field signal is only a small fraction of the normal transmitted bright-field signal, features can be revealed with high contrast, and it has proved possible to detect the presence of features that are below the resolution limit of the microscope

[en] Probed length scales of sub-micrometer dimensions have been achieved in photoemission spectroscopy owing to the high flux and brightness of the soft X-rays provided by the third generation synchrotron sources and the progress in microfabrication of focusing elements for soft X-rays. The use of multichannel detectors in the recently constructed scanning photoelectron microscopes adds speed and flexibility in data acquisition. Here we present some results obtained with the scanning photoemission microscope at ELETTRA illustrating the importance of the multichannel data acquisition for the interpretation of the data

[en] Differential phase contrast imaging in a scanning transmission electron microscope has been used to measure very narrow domain walls in the ferromagnetic alloy SmCo₅. This technique provides a more accurate and direct measurement of domain-wall structure than is possible with more conventional methods, and has allowed, for the first time, an experimental test of the predicted wall widths in highly anisotropic material

[en] The scanning photoelectron microscope (SPEM) on beam line 2.2 at the Elettra synchrotron produces small spot XPS spectra from a sub-micron radiation microprobe. It is also capable of producing surface images in terms of the energy resolved photoelectron signal. This microscope has been used to study oxidation on polycrystalline tin and lead surfaces and the variations in reactivity between different crystallite surfaces. The diffusion of gold and silver films on polycrystalline metal surfaces has also been followed

[en] A configured detector system based on an 80x80 element x-ray sensitive CCD array has been developed to replace the conventional transmitted x-ray detector used in the scanning transmission x-ray microscope. This from of detector allows a flexible choice of imaging modes to be made simultaneously from only a single scan of the sample. Details of the theoretical benefits expected, and the hardware implementation, are described

[en] Previously high-resolution soft x-ray microscopy has only been possible with synchrotron sources. Here, the first successful attempts at using a scanning transmission x-ray microscope with a laser-plasma source are reported. Spatial resolutions were limited to about 650 nm by electrical noise in the detector, but single shot per pixel images were obtained of test and real specimens. The microscope was not optimized to the source since it was designed for use on the undulator beam line of a synchrotron. With an improved system, it is demonstrated that single shot per pixel imaging at high resolution (better than 50 nm) will routinely be possible

[en] The article describes the ESCA microscopy beamline dedicated to high spatial resolution quantitative and qualitative analysis on surfaces and interfaces. The scanning microscope is constructed to work both in transmission and photoemission within the photon energy range from 200 to 1200 eV with a spatial resolution of ∼0.1 μm. A Fresnel zone plate demagnifies the photon beam to submicrometer dimensions with 10⁹--10¹⁰ photons/s in the focus spot. A photodiode and a hemispherical electron energy analyzer are used as detectors for recording the transmitted x-rays and emitted photoelectrons, respectively. The operation modes in photoemission give the opportunity to obtain conventional energy distribution curve spectra from a microspot or a two-dimensional micrograph of the spatial distribution and local concentration of a selected element as the sample is mechanically scanned. For conductive specimen topography measurements of a selected surface area probed by SPEM are possible using a scanning tunnelling microscope. The first test images of a zone plate and an e-beam written specimen with 1 μm² Au squares on Si have shown a spatial resolution better than 0.2 μm. copyright 1995 American Institute of Physics

[en] The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is micro structured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to poly capillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the micro probing of biological cells and tissue samples using Ti Ka radiation (4.5?keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics