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The two types of X-ray microscopes, scanning and full-field imaging, have different but complementary capabilities in term of image acquisition and spectroscopies. The novel approach used for the first time in the EU RT&D project “Twinmic" (HPRI-CT-2001-50024) aims at building of a multipurpose end-station combining scanning and full-field imaging microscopes with easy switch between the two modes. The twin microscope is expected to achieve the state-of-art performance of both microscopy modes in fast imaging, tomography and spectroscopy (μ-XANES/XRF), allowing new class of experiments in exploration of heterogeneous phenomena of the matter at mesoscopic length scales.

This paper reports an investigation of the oxidation state of Cr in samples of natural cements formed 500 ky ago in Maqarin (Jordan). The analyses were conducted using the Scanning Microscope from the ID21 beamline at the ESRF (Grenoble-France) operated in fluorescence mode. Cr(III) and Cr(VI) maps are collected on these samples at a resolution of 1 μm. The results suggest the slow oxidation of Cr(III) to Cr(VI) upon alteration of the cements in conditions of high pH and low to intermediate oxygen fugacity.

Using the scanning transmission X-ray microscope at ID21 beamline of the ESRF in fluorescence mode, we mapped tin at a bulk concentration of 1000 μg(Sn)/ml within hydrated tributyltin (TBT)-clay mineral (Kaolinite) dispersion with sub-300 nm spatial resolution. Using the Labsorption edges of tin at 3929, 4156 and 4465 eV fluorescence radiation was excited in tin atoms with incident photon energies of 4 and 4.5 keV. When using 4 keV radiation, only tin fluorescence is excited. For 4.5 keV X rays, both the fluorescence of tin and calcium (which is present in the solid phase) can be measured. Methodologically, we were interested in assessing and proving the possibilities and limitations of fluorescence mapping using the Labsorption edges of tin, where the fluorescence yield is significantly lower compared to other elements with their Kedges in the same energy range. Scientifically, organotin-clay mineral interactions are of environmental concern because this factor influences significantly the distribution of toxic TBT in the aquatic System. On one hand, the half-life of TBT deposited to the sediment phase increases, and consequently the time of its bioavailability. On the other hand, the adsorption process is reversible, which means that contaminated sediments can act as a source of pollution. The adsorption and desorption effects can be studied directly with high spatial resolution and brought into connection to the surface properties of the clay mineral under study as well as to other experimental parameters, like pH or salinity.

A soil with a high organic content, a calcaric phaeozem, has been imaged in a hydrated state using the Stony Brook scanning transmission X-ray microscope at the NSLS, Brookhaven, USA. This experiment has been performed at the carbon Kabsorption edge to determine the distribution of organic matter within this soil. Spectromicroscopic methods using the known spectra of humics are helping to distinguish between different kinds of carbon in the sample. In addition, a marsh soil from Northern Germany has been analyzed at the sulfur K-absorption edge with the scanning X-ray microscope at the ESRF (ID 21), Grenoble, France. This soil contains a variety of sulfur containing components, which are attached to the soil colloids. A major source of these components is the microbial activity. In this soil it is possible to identify spectroscopically amino acids like methionin and cysteine and proteins, which are built up from those molecules, and inorganic components like sulfates and sulfides.

It is commonly accepted that sulfur is carried out as sulfide (S$\rm ^{II-}$) or/and sulfate (S$\rm ^{VI}$) by Earth mantlederived melts, before being released as SO2and/or H2S in volcanic emissions. By analyzing reference compounds and a selection of minute glass inclusions in olivine crystals using μXANES (X-ray Near Edge Structure) spectroscopy at the sulfur K-edge, we demonstrated the ubiquitous presence of sulfite (S$\rm ^{IV}$) in addition to sulfate (S$\rm ^{VI}$) in these rare inclusions representative of oxidized and water rich-basaltic magmas, prior to loss of sulfur and water. The sulfide (S$\rm ^{II-}$) when exists is minor. We proposed that sulfite (S$\rm ^{IV}$) acts as an intermediate, metastable species which results in partitioning of sulfur into the volcanic gas emissions.

The evidence is increasingly strong that microorganisms developing around marine hydrothermal systems (thermophilic prokaryotes) were the first living community on Earth. Owing to the delicate nature of fossil microorganisms and inherent difficulties for discriminating between true fossils from artifacts, an important challenge for microbiologists and geochemists is to extract unequivocal beogenic information from individual microfossils using high-resolution and non-destructive techniques. Here, we report sub-micron scale mapping of transition metals (Fe, Zn and Cu) and sulfur oxidation states in individual filamentous microfossils using micro- PIXE (Proton Induced X-ray Emission) and synchrotron micro-XANES (X-ray Absorption Near Edge Structure) techniques. The sample studied consists of branching iron-oxide filaments encapsulated with amorphous silica from a fragment of an inactive chimney of the East Pacific Rise. Our results suggest that the original microorganisms were actively metabolising sulfur, and show the potential of the approach used for tracking microbial markers exploiting the full range of the sulfur-redox spectrum in fossilized hydrothermal systems.

X-ray imaging techniques at the best spatial resolution and using synchrotron facilities are put forth as powerful techniques for the search of small life forms in extraterrestrial rocks under quarantine conditions. Absorption and fluorescence X-ray microtomographies on sub-millimeter silicate assemblages inside a container reveal the mineralogical microenvironments were life should be looked for in priority. Limitations with respect to bacterial detection are due to the difficulties to obtain information about light elements ($Z \leq 14$), major constituents of biological and silicate samples. The X-ray signature of a “present" bacteria on a silicate surface was defined by X-ray mapping, out of a container, as coincident micrometer and oval zones having strong P and S fluorescence lines (S-fluorescence being slightly lower than P-fluorescence) and an amino-linked sulfur redox speciation. The detection of a single cell along with new procedures to calculate tomographic views will allow considerable improvements of 3D detection of life by X-ray techniques.

We describe a novel approach for converting the specimens phase information into strong image contrast in the x-ray region, the differential interference contrast x-ray microscopy (X-DIC). In the used setup, X-DIC operation was accomplished by a twin zone plate (TZP), i.e. two zone plates on both sides of the same substrate, laterally shifted by about one outermost zone width. Once a TZP has been successfully produced by means of especially developed nanofabrication processes, it is as easy to use as a single zone plate, without any alignment difficulty or further requirements to the coherence of the illumination. The tremendeous contrast enhancement was demonstrated at the microscopy beamline ID21 at ESRF in Grenoble for test objects and biological samples. TZPs allow for full field X-DIC imaging as well as for DIC scanning transmission x-ray microscopy. The first experiments were camed out at 0.31 nm wave] ength (4 keV photon energy), and features down to approx. 60 nm could be resolved in X-DIC.

New information about calcium status in human scalp hair shaft, deduced from X-ray microfluorescence imaging, including its distribution over the hair section, the existence of one or several binding-types and its variation between people, is presented. The existence of two different calcium types is inferred. The first one corresponds to atoms (or ions) easily removable by hydrochloric acid, located in the cortex (granules), in the cuticle zone and also in the core of the medulla, which are identified as calcium soaps cy comparison with X-ray diffraction and IR spectromicroscopy data. The second type consists of non-easily removable calcium atoms (or ions) that are located in the medulla wall, probably also the cuticle, and rather uniformly in the cortex; these calcium atoms may be involved in Ca2+-binding proteins, their concentration is fairly constant from one subject to another.

Blood cells of ascidians (tunicates) are known to accumulate high levels of vanadium selectively from sea water [1]. It has long been extensively studied how much vanadium is accumulated, which organ participate in the accumulation of vanadium, and what is the route of vanadium accumulation. However, they are not yet revealed completely. Micro-XANES is a powerful tool to investigate micro-distribution of chemical species of a given element. Fluorescence scanning X-ray microscope at ESRF (ID21), covering an energy range from 2 to 8 keV, has the capability of investigating chemical states of vanadium, sulfur, magnesium and calcium. In the present study, we have applied this X-ray scanning microscope in fluorescence mode to elucidate the distribution of vanadium in living ascidian blood cells. Using a cryogenic sample holder, local XANES spectra was also taken successfully. The valence of the vanadium in the cellis +3 and +4, judging from XANES spectra.

The widespread use of chromium in industrial applications such as chemical production of pigments, refractory brick production, tanning, metallurgy, electroplating, and combustion of fuels has lead to human occupational exposure and to its increased introduction into the environment. Hexavalent chromium compounds are established carcinogens but their mechanism of cell transformation is not known. Up to now, no microanalytical technique was sensitive enough to allow the observation of chromium distribution, and oxidation state identification, within isolated cells at carcinogenic concentrations. In this experiment, we used successfully the ID-21 X-ray microscope to map Cr(VI) and total Cr distributions in cells exposed in vitroto soluble, and insoluble, Cr(VI) compounds. Exposure to soluble compounds, weak carcinogens, resulted in a homogeneous intracellular distribution of Cr, confirming by in situmeasurement that Cr is present in the cell nucleus. Cr(VI) was never detected in cells which suggests a mechanism of rapid intracellular reducticn. On the other hand, exposure to insoluble compounds, strong carcinogens, also resulted in a homogeneous distribution of reduced forms of Cr in cells, and their nucleus. However, in this case, Cr(VI)-rich structures were observed into the cells suggesting that carcinogenicity is enhanced when oxidation reactions due to Cr(VI) chronic exposure are associated to Cr-DNA alterations.

The current intense interest in extrême ultraviolet and X-ray microscopy is mainly due to the availability of a nearly ideal optical source for diffractive optics (i.e. a source with low divergence whose wavelength can be tuned over a range of several keV and whose spectrum has a band pass $\Delta\lambda/\lambda$of less than 10-4). The aim of this paper is to introduce novel X-ray diffractive optics that, beside simple focusing, perform new optical functions. In particular, the intensity of the beam in the space after the optical elements can be redistributed with almost complete freedom. Using our own code we have designed high resolution diffractive elements which focus the monochromatic X-ray beam into multiple spots displaced in a single or more planes along the optical axis. These optical elements have been fabricated by means of e-beam lithography. Their functionality has been tested in two different X-ray microscopes: the scanning and the full-field imaging microscopes using the differential interference contrast method. We report experimental imaging results obtained with phase objects (PMMA and biological samples) and fluorescence measurements with important impact in the material science applications.

The Laboratory for Micro- and Nanotechnology provides the essential technologies necessary for the design and fabrication of diffractive x-ray optics for a wide range of applications. Over the past years, a large variety of optics has been fabricated and tested in collaboration with a large number of partners. To ensure good performance of the devices, they have to be tailored to the specific needs of a specific x-ray optical experiment in terms of photon energy and spatial coherence of the source, as well as required spatial resolution, working distance and diffraction efficiency. We report on a selection of such developments including transmission Fresnel phase zone plates for microscopy or microprobe applications at photon energies ranging from the EUV to the multi-keV region. For photon energies beyond 10 keV transmission zone plates are very rarely used. Our recent development of linear optics with ultra high aspect ratio structures has opened up a way to extend the applications of diffractive optics at least to the 30 keV range. Besides focusing elements, other diffractive optics such as decoherers or beam splitters for interferometric applications are presented.

High accuracy beamline instruments have been designed and developed for 12 years at the ESRF with an increasing demand of static and dynamic qualities. Over the last five years, microscopy beamlines, and more generally, the need for micro positioning when using small X-ray beams, has been a driving force for improving instrument compactness when combining movements, and a consequence has lead to a high level of intricacy. Even if resolutions of 0.1μm, and high quality guiding (70μrd), are easily found in commercially available translation stages, overall sizes and lever arms can lead to larger spheres of confusion. Moreover, environmental considerations such as vacuum compatibility can further restrict the choice of appropriate translations. To meet the various needs of the micro-focusing beamlines, compact and high-resolution micro-jacks, and xyz vacuum compatible cross tables have been developed in-house. A series of “standard” low profile components such as elevators (1 μm, 10mm). μrotary tables (Laue angle rocking curve), sample slits, inserted with either pico motors or stepper ujacks are now available. Using this approach an integrated “all in one” experimental station was designed for X-ray microscopy beamlines, like the scanning X-ray microscope for ID21, (10 sub-micron axes operated at 10-6mbars). Other versions are currently being developed for micro-fluorescence beamlines or post monochromators. The development programme has benefited greatly from the presence of the ESRF precision engineering laboratory (PEL), which allowed high quality metrology measurements to be performed on both the prototype and the final Systems.

This volume is the proceedings of the 7th X-ray microscopy conference, hosted by the ESRF, in Grenoble, from July 28th to August 2nd 2002. This triennial conference is the latest in a series of several conferences held successively in Gottingen (1983), Brookhaven (1987), London (1990), Chemogolovka (1993), Wurzburg (1996) and Berkeley (1999). The meeting series has become the principal international forum for the presentation and discussion of advances in high-spatial-resolution X-ray imaging and its applications across a broad range of sciences. XRM2002 was jointly supported by the ESRF, LURE and SOLEIL and attracted 239 participants from 18 nations.?In addition to providing the latest information on X-ray microscopy techniques, the programme was chosen to emphasise scientific accomplishments from various fields such as Biology, Earth Sciences, Materials Science, and Environmental Sciences. Both, the participation of 50 registered PhD students and the submission of more than 190 abstracts confirmed the rapid growth of the X-ray microscopy community. The 5-day conference featured 12 oral sessions and 3 poster sessions covering three generic areas: X-ray microscopy instrumentation, Applications, and Methods and Novel Approaches.?This book contains 150 reviews and status reports and closely reflects the progress of all the X-ray microscopy related fields. Papers are arbitrarily sorted by topical sections but an index gives also the correspondence with the original conference programme. The three first sections cover instrumental developments in X-ray microscopy and report on synchrotron facilities and new instruments (24 papers), laboratory instruments and compact sources (12 papers), and finally on X-ray optics (28 papers). The next five chapters are concerned with applications of X-ray microscopy related techniques and present contributions on biological and medical sciences (20 papers), earth and planetary sciences (8 papers) environmental and soils sciences (12 papers), materials and surface sciences (15 papers), and archeometry (2 papers). Finally, the two last chapters are devoted to new methods and coherent imaging (18 papers) and data processing and software developments (9 papers), respectively. Because of the large number of contributions, the length of the papers was strictly limited and, while most of them can be directly identified with conference presentations, in a few cases papers on similar topics were combined.