Platform probes materials compressed to millions of atmospheres with X-ray diffraction
Platform probes materials compressed to millions of atmospheres with X-ray diffraction lead image
At extreme pressures greater than 1 million times that of at sea level, core electrons on neighboring atoms begin to interact, and matter has been observed to exhibit a variety of exotic behaviors. These dramatic changes in material properties under pressure have a number of practical consequences, including for the structure and evolution of astrophysical bodies and for various terrestrial applications such as inertial confinement fusion.
Rygg et al. present an experimental platform for characterizing materials compressed to extreme pressures in excess of 2 terapascals, or 20 million atmospheres, using in situ X-ray diffraction at the National Ignition Facility (NIF). A gradual increase in the NIF drive-laser irradiance elevates the material sample to such extreme pressures over tens of nanoseconds, with pressure determined using high-precision velocimetry. An X-ray source is flashed using additional laser beams when the sample is at a high, uniform pressure, and diffraction from the compressed sample is recorded over 1.5 steradians.
The work is the culmination of the efforts of a large team of scientists and engineers to design, fabricate and characterize the target, shielding, detectors and laser pulses required to accomplish these measurements. The team reports details regarding the setup and performance of the experimental platform.
“For over a century, X-ray diffraction has been a workhorse technique for scientific discovery and the understanding of materials,” said author James Ryan Rygg. “We are pleased to push this capability toward the frontier of high-pressure science.”
Rygg states that a series of scientific articles will soon follow that have used this platform to investigate the compressibility and atomic structure of several materials at the highest pressures yet reported for X-ray diffraction.
Source: “X-ray diffraction at the National Ignition Facility,” by J. R. Rygg, R. F. Smith, A. E. Lazicki, D. G. Braun, D. E. Fratanduono, R. G. Kraus, J. M. McNaney, D. C. Swift, C. E. Wehrenberg, F. Coppari, M. F. Ahmed, M. A. Barrios, K. J. M. Blobaum, G. W. Collins, A. L. Cook, P. Di Nicola, E. G. Dzenitis, S. Gonzales, B. F. Heidl, M. Hohenberger, A. House, N. Izumi, D. H. Kalantar, S. F. Khan, T. R. Kohut, C. Kumar, N. D. Masters, D. N. Polsin, S. P. Regan, C. A. Smith, R. M. Vignes, M. A. Wall, J. Ward, J. S. Wark, T. L. Zobrist, A. Arsenlis, and J. H. Eggert, Review of Scientific Instruments (2020). The article can be accessed at https://doi.org/10.1063/1.5129698 .
