Three-Dimensional Elemental Imaging of Nantan Meteorite via Femtosecond Laser Ionization Time-of-Flight Mass Spectrometry.

Femtosecond laser ionization time-of-flight mass spectrometry (fs-LI-TOFMS) is introduced for the three-dimensional elemental analysis of a Nantan meteorite. Spatially resolved multielemental imaging of major and minor compositions in a meteorite are presented with a lateral resolution of 50 µm and a depth resolution of 7 µm. Distinct 3D distributions of siderophile, lithophile, and chalcophile elements are revealed. Co and Ni are highly siderophile (Iron-loving), mainly enriched in the metal phase. Cr, Cu, V, and Mn are enriched in the sulfide for their chalcophile (S-loving) tendency. S, P, and C aggregate together in the analytical volume. Silicate inclusion, containing lithophile elements of Al, Ca, Mg, K, and so on, is embedded within the metal phase for the immiscibility between silicate inclusion and the melted metal phase. These 3D distributions of elements aid the exploration of the formation and evolution of the meteorite. They also reveal the feasibility of fs-LI-TOFMS as a versatile tool for 3D imaging.

Note: Measurement method for sound velocity of melts in large volume press and its application to liquid sodium up to 2.0 GPa.

Based on large volume press and conventional pulse-echo ultrasonic technique, we have overcome the difficulty in determining the length of liquid specimen under high pressure, and the sound velocity in liquid Na has been measured up to 2 GPa. The P-V data deduced by our sound velocity results through equation of state is in an excellent agreement with previous data directly determined by piezometer method. This new experimental technique is convenient and ready for use, being expected to advance investigation on thermodynamic properties of liquid metals and other melts under high pressure.

A simple external resistance heating diamond anvil cell and its application for synchrotron radiation x-ray diffraction.

A simple external heating assemblage allowing diamond anvil cell experiments at pressures up to 34 GPa and temperatures up to 653 K was constructed. This cell can be connected to the synchrotron radiation conveniently. The design and construction of this cell are fully described, as well as its applications for x-ray diffraction. Heating is carried out by using an external-heating system, which is made of NiCr resistance wire, and the temperature was measured by a NiCr-NiSi or PtRh-Pt thermocouple. We showed the performance of the new system by introducing the phase transition study of cinnabar (alpha-HgS) and thermal equation of state study of almandine at high pressure and temperature with this cell.