Laboratory X-ray Microscopy Research Articles

Laboratory x-ray microscopy using a reflection target system and geometric magnification

This paper describes a laboratory X-ray microscopy setup, based on geometric magnification. The setup uses a sharp metal tip as a reflection target and a highly focused electron beam of a scanning electron microscope. Here we will describe the structuring process for these metal targets. To demonstrate the capabilities of our system, we show radiographs of test structures corresponding to resolutions below 100nm. There are abilities for 3D imaging in later updates of the system. Further we discuss the first imaging examples for high- and low-absorbing samples.

The Stockholm laboratory cryo x-ray microscope: towards cell-cell interaction studies

We describe recent improvements in the Stockholm laboratory x-ray microscope and the first experiments aiming towards studies of cell-cell interaction. The shorter exposure time due to a higher brightness laser-plasma source will become of large importance for tomography while the reproducible cryo preparation of few-cell samples is essential for the interaction studies.

LiF detectors-polycapillary lens for advanced X-ray imaging

A great effort in X-ray imaging studies has been dedicated to the design of novel optics-detector solutions that aims in creating a compact laboratory X-ray microscopy apparatus. Based on our experience in the use of both capillary/polycapillary optical systems and LiF imaging detectors we have recently tested a new combination of these techniques. The potential of the optics both to concentrate and to shape X-ray radiation enforced by the high performances in terms of spatial resolution/dynamic range of LiF imaging detectors allows us to use very simple imaging techniques, like the contact one, particularly suitable for compact imaging systems. In this paper we present first results about high spatial resolution images of transmitted X-rays through a polycapillary semi-lens. Submicron X-ray imaging of thick geological samples was also presented and discussed. These results demonstrate the potentialities of these novel X-ray imaging system for characterization of X-rays optics and for applications in material, life and heart sciences.

Comparison of different sources for laboratory X-ray microscopy

This paper describes the setup of two different solutions for laboratory X-ray microscopy working with geometric magnification. One setup uses thin-film transmission targets with an optimized tungsten-layer thickness and the electron gun and optics of an electron probe micro analyzer to generate a very small X-ray source. The other setup is based on a scanning electron microscope and uses microstructured reflection targets. We also describe the structuring process for these targets. In both cases we show that resolutions of 100 nm can beachieved. Also the possibilities of computed tomography for 3D imagingare explored and we show first imaging examples of high-absorption aswell as low-absorption specimens to demonstrate the capabilities ofthe setups.

Laboratory X-ray microscopy with a nano-focus X-ray source

In this paper we describe the optimization of transmission X-ray targets by Monte-Carlo simulation for a laboratory X-ray microscopy setup. We identified two optimal target layer thicknesses (0.1 μm and 0.7 μm) for a high-resolution target and a high-flux target. Measurements show a decrease in focal spot size by one third or an increase in X-ray flux by a factor of three compared to those of a standard micro-focus target. Focal spot sizes down to 154 nm and 260 nm are achievable with the optimized targets. Simulation results for the X-ray flux match well to the experimental results, whereas the results for the focal spot sizes still show discrepancies attributed to the simplified simulation setup.

Laboratory X-ray microscopy for high-resolution imaging of environmental colloid structure

Transmission X-ray microscopy is a uniquely suited technique for studies of environmental colloids since it allows imaging in aqueous media with high spatial resolution, presently down to the 20nm range. Such nano-scale morphological description of these high-specific-surface-area compounds show promise for improved understanding of soils, sediments or groundwater aquifers. However, present high-quality X-ray microscopes are located at synchrotron radiation facilities resulting in limited applicability and accessibility for colloid scientists. Here we investigate the applicability of a laboratory-scale transmission X-ray microscope for studies of colloids of the environment. The microscope is based on a laser-plasma source in combination with multilayer and zone plate optics. Samples are held at atmospheric pressure in their natural wet state. We show images revealing the nano-scale morphology of the clay nontronite, soils such as chernozem and luvisol, and the mineral hematite, an iron oxide. Comparative studies of dried substances clearly show the need for imaging in the wet state. The image quality approaches that of synchrotron-based microscopes, albeit at longer exposure times. Stereo imaging is investigated as a means for giving 3D information with shorter exposure times than tomography requires. Finally the future development of the laboratory X-ray microscope is discussed, especially with regard to the reduction of exposure times.

Laboratory X-ray microscopy with reflective – refractive lens system

Compound refractive lens (CRL), consisting of a number of in-line placed concave microlenses made of low-Z material, is a unique imaging X-ray device. An experiment combining the CRL manufactured by the method described in [1] and working as an objective with the reflective micromirror as ta condenser and X-ray microfocus source is presented. The system was used as an X-ray microscope working at 8 keV X-rays and also for demonstration of demagnified imaging.

High-resolution imaging of soil colloids in aqueous media with a compact soft X-ray microscope

Colloids play an important role when describing parameters of and processes within soils, sediments or aquifers due to their abundance and their high specific surface area. It is of great importance to visualize the morphology of the structures formed by these particles as close as possible to environmental conditions. With X-ray microscopy colloids from the environment can be imaged directly in aqueous media with high spatial resolution. We demonstrate the first use of a compact laboratory x-ray microscope for studies of colloids from the environment, namely aqueous suspensions of clays and soils. The microscope is based on a high-brightness laser-produced-plasma X-ray source, a multilayer mirror and diffractive optics. The experiments show that such compact X-ray microscopes are reaching the image quality and operational maturity to make a significant impact in fields like environmental sciences.

Sub-25-nm laboratory x-ray microscopy using a compound Fresnel zone plate

Improving the resolution in x-ray microscopes is of high priority to enable future applications in nanoscience. However, high-resolution zone-plate optics often have low efficiency, which makes implementation in laboratory microscopes difficult. We present a laboratory x-ray microscope based on a compound zone plate. The compound zone plate utilizes multiple diffraction orders to achieve high resolution while maintaining reasonable efficiency. We analyze the illumination conditions necessary for this type of optics in order to suppress stray light and demonstrate microscopic imaging resolving 25 nm features.