New measurement of diamond phase change could mean increased ICF energy gain

[Marlin]

New measurement of diamond phase change could mean increased ICF energy gain

https://www.ans.org/news/2026-08-14/article-8296/new-measurement-of-diamond-phase-change-could-mean-increased-icf-energy-gain/

[Core Content]

Researchers at Lawrence Livermore National Laboratory have resolved a long-standing discrepancy regarding the melting temperature of diamond under extreme pressure. By utilizing X-ray diffraction at the University of Rochester, the team successfully measured diamond phase changes during laser-driven compression. These results align experimental data with theoretical models for the first time.

This refined understanding of diamond behavior directly impacts inertial confinement fusion experiments at the National Ignition Facility. Diamond capsules currently hold deuterium-tritium fuel, but uneven melting can cause hydrodynamic instabilities that disrupt implosions. By accurately predicting phase changes, researchers can now utilize lower-entropy, slower first shocks to increase fuel compression and maximize total energy yield during fusion ignition.

Researchers at Lawrence Livermore National Laboratory have measured how diamond melts under extreme pressures, resolving a long-standing discrepancy between experiment and theory. In inertial confinement fusion experiments, where a diamond capsule is used to hold fuel, this refined understanding of diamond's phase change has the potential to...

"We were able to take tiny diamond samples and shock compress them to temperatures hotter than the surface of the sun and to pressures higher than the center of Neptune and Uranus—and still measure atomic structure, temperature, density, and optical reflectivity," said LLNL scientist Marius Millot.

The experiment: The team conducted laser-driven dynamic compression experiments at the University of Rochester's Laboratory for Laser Energetics (LLE), where they compressed a tiny diamond sample and captured information such as X-ray diffraction data that illuminates atomic structure, all in a billionth of a second. The results were published yesterday in Nature Physics.

Read the full article at ans.org:
https://www.ans.org/news/2026-08-14/article-8296/new-measurement-of-diamond-phase-change-could-mean-increased-icf-energy-gain/