A new diamond anvil cell for hydrothermal studies to 2.5 GPa and from −190 to 1200 °C

Abstract

A new style of diamond anvil cell (DAC) has been designed and built for conducting research in fluids at pressures to 2.5 GPa and temperatures from-190 to 1200 "C. The new DAC has been used for optical microscope observations and synchrotron x-ray diffraction studies. Fringes produced by interference of laser light reflected from top and bottom anvil faces and from top and bottom sample faces provide a very sensitive means of monitoring the volume of sample chamber and for observing volume and refractive index changes in samples that have resulted from transitions and reactions. X-ray diffraction patterns of samples under hydrothermal conditions have been made by the energy dispersive method using synchrotron radiation. The new DAC has individual heaters and individual thermocouples for the upper and lower anvils that can be controlled and can maintain temperatures with an accuracy of ho.5 "C. Low temperatures are achieved by introducing liquid nitrogen directly into the DAC. The equation of state of Hz0 and the a-0 quartz transition are used to determine pressure with an accuracy of f 1% in the aqueous samples. The new DAC has been used to redetermine five isochores of Hz0 as well as the dehydration curves of brucite, Mg(OH)z, and muscovite, Kkl,(Si,Al)O,,(OH),.-2340 Rev. Sci. Instrum.

Equations of state of hexanitrostilbene (HNS)

“…High temperatures were achieved by using a hydrothermal diamond anvil cell (HDAC), developed by Bassett et. al [5]. In this cell heating coils are in contact with both diamonds.…”

Structural organization and phase behaviour of 1-butyl-3-methylimidazolium hexafluorophosphate: an high pressure Raman spectroscopy study

“…The experiments were performed using a high resolution Raman spectrometer and an externally heated Bassett-type hydrothermal diamond-anvil cell (HDAC) 36 with ultra-low fluorescence grade anvils. The sample chamber of the cell, a 300 mm hole in the Re gasket separating the anvils, was loaded with a grain of quartz, which served as a Raman spectroscopic pressure sensor, 37 Unpolarized Raman spectra were obtained using a HORIBA Jobin Yvon LabRAM HR800 UV-Vis Raman microprobe (gratings 1800 lines mm…”

Speciation in Aqueous MgSO4Fluids at High Pressures and High Temperatures from ab Initio Molecular Dynamics and Raman Spectroscopy

“…An externally heated Bassett-type hydrothermal diamond-anvil cell (HDAC) 36 equipped with type Ia ultra-low fluorescence grade diamond anvils (culet diameter 0.9 mm) was used as optical cell.…”