These instruments allow the simultaneous compression and heating of millimeter size solid phase samples such as rocks, minerals, ceramics, glasses, composite materials, or metals and are capable of reaching pressures above 25 GPa (around 250,000 atmospheres) and temperatures exceeding 2,500 °C.
This allows mineral physicists and petrologists studying the Earth's interior to experimentally reproduce the conditions found throughout the lithosphere and upper mantle, a region that spans the near surface to a depth of 700 km.
Lawrence Livermore National Laboratory's two presses have been used for a variety of material property studies, including diffusion and deformation of ceramics and metals, deep-focus earthquake, and the high-pressure stability of mineral phases.
In 1990, Walker et al.[4] simplified the first compression stage by introducing the removable hatbox design, allowing ordinary machine presses to be converted into multi-anvil systems.
A typical Kawai cell 8–6 multi-anvil apparatus uses air pumps to pressurize oil, which drives a vertical hydraulic ram to compress a cylindrical cavity known as a hatbox.
[8] The DIA multi-anvil design often includes diamond or sapphire windows built into the tungsten anvils to allow x-rays or neutrons to penetrate into the sample.
[10] This type of device gives researchers at synchrotron and neutron spallation sources the capacity to perform diffraction experiments to measure the structure of samples under extreme conditions.
Multi-anvil presses are occasionally used in industry to produce minerals of exceptional purity, size and quality, especially high-pressure high-temperature (HPHT) synthetic diamonds and c-Boron-Nitride.
[citation needed] Geoscientists also use multi-anvils to measure the kinetics of reactions, density, viscosity, compressibility, diffusivity and thermal conductivity of rock under extreme conditions.