ERL and Internal Resistive Heating for the DAC
Chang-Sheng Zha1,*, William Bassett2, Kenji Mibe2,3, Oliver Tschauner4
1Cornell High Energy
Synchrotron Source, Cornell University
2Department of Earth
and Atmospheric Sciences, Cornell University
3Earthquake
Research Institute, University of Tokyo
4High Pressure Science
and Engineering Center and Department of Physics, University of Nevada, Las
Vegas
*Present address: Carnegie Institution of
Washington, Geophysical Laboratory
An internal heating system has been developed for the diamond anvil cell (DAC). With it samples 10 microns in diameter can be subjected to pressures up to 80 GPa and 1900K. These temperatures and pressures are higher than can be achieved with external heating and are more uniform and constant than can be achieved with laser heating. X-ray diffraction (XRD) and X-ray fluorescence (XRF) are among the most basic analytical tools for studying samples at these conditions. Although third-generation synchrotron sources provide small, very brilliant X-ray beams, it is beam size and brilliance that limit what can be accomplished.
Some important benefits and experiments that can result from combining internally heated DAC and an ERL beam.
1. Increasing experimental conditions to higher pressures and temperatures will require smaller heaters and samples. To gain enough signal intensity and avoid interference from the heater, we need a very brilliant and exceedingly small X-ray beam.
2. Determination of melting pressures and temperatures up to conditions of magma formation within the Earth will be possible by X-ray diffraction in the internally heated DAC using an X-ray beam that is small enough and brilliant enough.
3. Determination of compositions and crystal structures of individual grains of solid phases coexisting with the melt phase will be possible by X-ray fluorescence and diffraction in the internally heated DAC using a very small and brilliant X-ray beam. If the beam is sufficiently small, imaging may be possible by rastering.
Determination of elastic properties may be possible by using a nano-size ERL beam to probe individual single-crystal grains in a sample subjected to high pressures and temperatures and to determine their anisotropic elastic strain from their Laue patterns. Accurate equation of state determinations, deviatoric stress, strength measurements, and pressure measurements would all benefit from this information.
