Shock-ramp compression of Au pressure standard on the Z machine

Having a well-established pressure standard is an essential component of experiments on matter at extreme conditions. Au is a commonly used pressure standard in static and dynamic compression experiments and has been studied extensively in the diamond anvil cell and shock compression (1,2). Recently Au has been studied up to 1 TPa using ramp compression (1). Shock-ramp compression provides a unique way to study matter at extreme conditions by probing phase space that is lower in temperature than shock compression and higher in temperature than ramp compression. This work presents an analysis of a shock-ramp compression experiment on the Au pressure standard using Sandia National Laboratories’ Z machine. The measurements further reduce uncertainties in the Au standard pressure calibrant by probing P-T ranges not accessible through pure shock or shockless compression experiments.

1. K. Takemura and A. Dewaele, Isothermal equation of state for gold with a He-pressure medium. Phys. Rev. B, 78, 104119 (2008).

2. M. Yokoo et al., Hugoniot measurement of gold at high pressures of up to 580 GPa. Appl.Phys. Lett. 92, 051901 (2008).

3. D. E. Fratanduono et al., Establishing gold and platinum standards to 1 terapascal using shockless compression. Science 372, 1063-1068 (2021).