Probing the Kinetics of the Alpha–Epsilon Phase Transition in Shock-Compressed Iron Using Time-Resolved X-Ray Diffraction

A method of measuring multiple temporally resolved powder x-ray diffraction (XRD) measurements during a single laser experiment has been demonstrated on shock-compressed iron at the Omega EP Laser Facility. Using a variation of the time-integrating powder XRD image-plate configuration, up to four temporally resolved snapshots of the XRD pattern are collected on an x-ray framing camera with a 2θ scattering angle coverage of 48° to 66° with a 400-ps temporal resolution.[1] XRD snapshots of the alpha–epsilon phase transition in iron capture the shock-transit, shock-breakout, and shock-release evolution, providing insight into the time dependence of the transformation.

[1] J. R. Rygg et al., Rev. Sci. Instrum. 83, 113904 (2012).