Exploring toroidal anvil profiles for larger sample volumes above 4 Mbar

Area of Science:

• High-pressure physics and materials science
• Planetary science and geophysics
• Diamond anvil cell technology

Background:

• Toroidal and double-stage diamond anvil cells (DACs) achieve high static pressures (4-10 Mbar) but have limited sample volume.
• Larger sample volumes in DACs are crucial for diverse applications in physics, chemistry, and planetary science.
• Exploring planetary interiors requires characterizing materials under extreme pressures and temperatures.

Purpose of the Study:

• To investigate larger toroidal DAC profiles for enhanced sample volume capabilities.
• To test and validate the performance of novel large-culet toroidal anvil designs.
• To enable new research avenues in materials science and planetary interior studies.

Main Methods:

• Iterative testing of toroidal DAC profiles with varying torus/shoulder depths and culet diameters (30-50 µm).
• Pressure calibration using a platinum (Pt) scale.
• Equation of state (EOS) measurements using gold (Au) and rhenium (Re) as pressure standards at 300 K.

Main Results:

• A 30 µm culet toroidal DAC profile achieved a maximum pressure of 414(1) GPa.
• Pressure-volume (P-V) data for gold and rhenium are consistent with extrapolated hydrostatic EOS up to 4 Mbar (within 1%).
• The developed toroidal anvils demonstrate reliable performance exceeding 4 Mbar.

Conclusions:

• Large-culet toroidal DACs are validated for pressures exceeding 4 Mbar.
• These anvils provide a robust platform for diverse sample loading and laser heating experiments.
• This advancement supports future research into super-Earth and sub-Neptune interior conditions and novel material synthesis.