The internal resistive heating method developed at CHESS has advantages in temperature homogeneity and stability over conventional laser heating method, so the precise and reliable P-V-T equation of state measurements become possible.
The unique feature of internal resistive heating program at CHESS:
Chang-Sheng Zha
Cornell High Energy Synchrotron Source, Wilson Lab, Cornell University, Ithaca, NY 14853
1. Internal resistive heating method has strikingly improved the temperature quality produced inside the diamond anvil cell (homogeneity and stability), which makes precise, reliable measurements for P-V-T equation of state possible.
2. Raman spectroscopy at simultaneous high P and high T is of great importance for probing phase transition and bonding relations at those extreme conditions. Combined this technique to synchrotron radiation source would enhance the ability to characterize these transition and bond relations. Internal resistive heating DAC makes easier way for this combination
How high temperature we can produce in the DAC?
3000 K. (collaborator: William A. Bassett, [Cornell U.] paper titled Internal resistive heating in diamond anvil cell for in situ x-ray diffraction and Raman scattering. Review of Scientific Instruments, 74(3), Part 1, 1255, 2003)
The internal resistive heating method developed at CHESS has advantages in temperature homogeneity and stability over conventional laser heating method, so the precise and reliable P-V-T equation of state measurements become possible.
In situ high PT Raman spectroscopy at synchrotron
P-V-T equation of state for rhenium by in situ x-ray diffraction at simultaneous pressure-temperature conditions, Chang-Sheng Zha1, William A. Bassett2 and Sang-Heon Shim3; 1Cornell High Energy Synchrotron Source, Wilson Laboratory, Cornell University, Ithaca, NY 14853 2Department of Geological Sciences, Cornell University, Ithaca, NY 14853 3Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
When the P-V-T EOS is known, the temperature dependences of volume at constant pressure can be obtained. The volume coefficients of thermal expansion for rhenium are evaluated from 
as shown below
Raman spectra of cubic boron nitride (c-BN) at high pressure and elevated temperatures. The insert shows the plot of temperature verses pressure estimated according to independent temperature and pressure calibrations of Raman shift. The straight line represents the average pressure by the estimation. It needs to be recalibrated at simultaneous PT condition with in situ x-ray diffraction to create this material as a optical pressure sensor at high temperature.
Raman spectra of SiO2 glass before, during, and after heating. The strong coesite peak around 534 cm-1 appeared during heating to 1250 K; however, the pressure was unknown. The pressures noted for before and after heating were measured by ruby fluorescence scale. The peak width at high temperature is obviously broader than that at room temperature.
