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A new technique for density measurement of molten materials in a multi-anvil press using synchrotron X-ray radiography is described. This technique takes advantage of a linear conversion of X-ray intensity to radiograph brightness, and records two-dimensional variations in transmitted X-ray intensities across a reference sphere in the sample on a single exposure. Comparing with the existing technique of one-dimensional scan using a small beam of X-rays for the melt density measurement at high pressure, this method gains a shorter data collection time and larger data coverage (two-dimensional). Melting volume of FeS at 4.1 GPa is determined to be 0.28 cm³/mol and slope of the melting curve is estimated to be 41°C/GPa. This experiment demonstrates an accuracy of 1% for the density measurement with respect to X-ray diffraction method for crystalline phase. [ABSTRACT FROM AUTHOR]

Synchrotron X-rays coupled with high-pressure deformation facilities have transformed the tools for studying the rheological properties of materials at high pressure and temperature. The new D-DIA device is capable of producing 15 GPa of pressure at 2000 K and simultaneously introducing a differential stress field that can attain steady state flow with strains reading in excess of 50%. X-ray transparent anvils enable diffraction in both the vertical and horizontal directions, providing sufficient information to define differential stress in the sample while the strain rate is monitored by X-ray images. This new tool opens the door to new studies relevant to the processes deep within the Earth, illuminating the dynamics of deep earthquakes and mantle flow. [ABSTRACT FROM AUTHOR]

A preface for the book "Advances in High Pressure Techniques for Geophysical Applications" is presented.