Data Tables for Primary Pressure Scale of KCl B2 Phase to the Core-Mantle Boundary.xlsx

Reliable pressure determination is crucial for high pressure and temperature experiments and meaningful interpretation of their geophysical implications. However, nearly all commonly-used pressure scales such as equation of states (EOS) on reference materials, Ruby fluorescence and diamond anvil Raman gauges are secondary in nature, meaning they were calibrated based predominantly on shock-compression-based pressure standards, which itself has substantial uncertainties. In this study, a self-consistent primary pressure scale of KCl B2 phase was experimentally calibrated up to 85 GPa at ambient temperature through simultaneously measuring the acoustic wave velocities and molar volume using Brillouin spectroscopy and Synchrotron X-ray diffraction (XRD). The resulted EOS, in combination with thermal pressure calculated using Mie‒Grüneisen‒Debye model enables accurate pressure determinations at simultaneously high pressure and temperature conditions up to Earth’s core-mantle boundary (CMB) and can serve as a benchmark for calibrating other secondary pressure scales.