High-pressure experimental science has traditionally followed two very different approaches, static and dynamic. Static and dynamic experiments are powerful complimentary approaches that have progressed in parallel to advance a comprehensive scientific understanding of materials properties at high pressures. Static experiments employ a comprehensive set of diagnostics, but do not address dynamic properties. Shock experiments are by their very nature dynamic, but are not suited to many conventional diagnostic techniques. To address these limitations, we have developed a dynamic DAC (dDAC) to probe the dynamic high-pressure properties of materials at compression rates intermediate to shock and static approaches.
In this presentation we will describe our dynamic-DAC (dDAC), which aims to bridge the gap between static and dynamic experiments and address issues regarding dynamic material properties and the kinetics of transformations at high pressures. The dDAC is an enhancement on the design of conventional diamond anvil cells (DAC). A simplified description of our dDAC design is a conventional DAC incorporating piezo-electric actuators that drive a load supplementing the main load provided by the conventional load screws. Using a function generator we drive a tailored time-dependent pressure profile on a sample. This approach allows us to adapt existing DAC ancillary instrumentation for loading samples and experimental studies. We will describe the characteristics of this device’s operations and results of recent experiments. Studies of water demonstrate dramatic compression rate-dependent changes in the morphology, growth rate and phase of the ice crystals. The dDAC is an important tool for studying dynamic properties of materials, an important area of study that should be rich in new physical phenomena.