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The absorption cross section of a number of calcium salts has been assessed at the calcium L edge by measuring the total electron yield (TEY) at the NSLS U13UA beamline. TEY was used because of distortions introduced by instrumentation when using a transmission signal. The effect of these distortions has been evaluated and is presented. The TEY signal was normalized to the incident beam using the signal from a new beam monitor which is detailed here. Comparative spectra are presented for some calcium salts associated with osteoarthritis.

Two laboratory scale x-ray microscopes using laser generated plasma sources are being developed at King's College. One system uses dark field imaging while the other is a scanning x-ray microscope and progress with both is described. In particular, preliminary results from an extensive characterisation of the laser plasma source at the Lasers for Science Facility, CLRC Rutherford Appleton Laboratory, are discussed. This characterisation has shown that the source is eminently suitable for x-ray microscopy.

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Ultra-thin unstained sections of femoral neck bone from normal and ovariectomised mice were imaged in a scanning transmission x-ray microscope. The images were formed using soft x-ray energies at the calcium L and carbon K edges. The aim of the study was to quantitatively map the calcium, protein and embedding medium in normal and ovariectomised (osteoporotic) mice to compare the quantity and distribution of mineral (via calcium), collagen (via protein) and hydrated content (via embedding medium substitution).A set of seven images were taken of both the normal and ovariectomised mouse sections. These images were processed using x-ray optical constants to produce mass thickness maps. The thickness of the sections from the normal mouse and ovariectomised mice were 205nm and 375nm respectively. The images show embedding medium, protein and calcium maps of near complete sections of the majority of the femoral neck at equivalent neck positions in the normal (la, 2a & 3a) and ovariectomised (lb, 2b & 3b) mouse bone sections.