A multiple-calibrant technique for room-temperature pressure calibration in multi-anvil experiments

The multi-anvil experimental technique is widely used in solid Earth and planetary sciences, as well as material sciences, for the generating high-pressure (up to 120 GPa) and high-temperature (above 3500 K) conditions in a relatively large sample volume (typically 1-10 mm3). Despite its ability to achieve extreme conditions, determining the exact pressure in a multi-anvil experiment is challenging. It is typically estimated using pressure calibration curves; however, constructing pressure calibration curves requires conducting numerous preliminary pressure calibration experiments. In this study, we developed a convenient experimental technique for room-temperature pressure calibration by modifying the cell assembly design, in which multiple calibrants (with a theoretical maximum of seven calibrants) can be loaded within a single assembly. Consequently, multiple data points for a pressure calibration curve can be acquired in one experimental run. This technique significantly reduces the effort required to construct a pressure calibration curve for multi-anvil experiments.