X-ray microtomography for studying localized deformation in fine-grained geomaterials under triaxial compression

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In situ high-energy X-ray diffraction study of a bioactive calcium silicate foam immersed in simulated body fluid

The method of in situ time-resolved high-energy X-ray diffraction, using the intrinsically highly collimated X-ray beam generated by the European Synchrotron Radiation Facility, is demonstrated. A specially designed cell, which allows the addition of liquid components, has been used to study the reaction mechanisms of a foamed bioactive calcia-silica sol-gel glass immersed in simulated body fluid. Analysis of the X-ray diffraction data from this experiment provides atomic distances, via the pair correlation functions, at different stages of the dissolution of the glass and of the associated calcium phosphate, and ultimately hydroxyapatite, i.e. bone mineral, formation. Hence, changes in the atomic scale structure can be analysed as a function of reaction time, giving an insight into the evolution of the structure of both the glass matrix and the hydroxyapatite surface growth

Scanning X-ray spectrometer for high-resolution Compton profile measurements at ESRF

uorescent lines. So far, 0.1 a.u. resolution in electron momentum has been achieved. The typical average count rate over the Compton prole is about 1000 counts s #1 from a weakly absorbing sample. Keywords: Compton scatterings; X-ray spectrometers. 1. Introduction It was very shortly after the initial discovery by A. H. Compton when it was realised that the electron momentum prior to the scattering event should cause a Doppler broadening of the Compton line. It was suggested by J. W. M. DuMond that the Doppler broadening could be used for studies of electronic states of atoms, and he built the rst Compton spectrometer in the late 1920s. This was soon developed into a focusing spectrometer, based on the principle that is now called Cauchois geometry. There were 50 small calcite crystals on the Rowland circle orientated to reect a given energy at one point on the opposite side of the Rowland circle. The radiation reected by the analyser crystals was recorded on photographic lm and