High pressure Laboratory (MBar)
By using a diamond anvil cell (DAC) it is possible, in the laboratory, to reach a static pressure of the order of a million bar. Measurements in such extreme conditions have a fundamental importance for geophysics, planetology, material science, chemistry, fundamental physics and so on. The technology involved is particularly advanced: the sample, having about a hundred micron size, is pressed between two diamonds, and laterally contained by a metal gasket. The scheme of a DAC is reported in figure. We have at our disposal several cells, designed and built in our laboratory, of the membrane type, that is, where the force pushing the diamonds one against the other is generated by inflating with a gas (typically helium) a metal diaphragm. This method allows one to control remotely and finely the pressure in the sample, for cryogenic or optical application (that is, when the cell is inside a cryostat or aligned in and optical system). Filling the cell requires different technologies depending whether the sample (at normal conditions) is a solid, a liquid or a gas. A gas loading system (for gas samples or for solid samples to be measured in an almost hydrostatic environment) is present in our laboratory. This device, (designed and built in our laboratory) consist of an autoclave where the cell is immersed into a gas at several thousands of bar. A spark-erosion system (to drill holes of a few tens of a micron into the gasket) is also present in our laboratory.

Photograph of the membrane DAC used in our studies

By means of our spectroscopy instrumentation (see Raman Laboratory) we can measure Raman spectra from samples at simultaneous high pressure (from 2 kbar to 1 Mbar) and low temperature (down to about 4 K).
Complex Systems Institute Florence section - CNR research area
Via Madonna del Piano, 10 - 50019 Sesto Fiorentino (FI) Italy
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