Fission Experiments in Laser-Generated Plasmas

Alex Zylstra | 20-ERD-031

Project Overview

Nuclear physics is traditionally studied at ambient conditions with solid room-temperature targets irradiated by beams of particles. However, in important scenarios for astrophysics, nuclear reactions occur in an extreme high-energy-density plasma environment, where pressures can exceed millions or billions of atmospheres. In these environments, the nuclear physics can be affected by the plasma environment or nuclei can be exposed to fluxes of neutrons, photons, and charged particles orders of magnitude higher than traditional laboratory sources; nuclear excited states can be populated in these environments and affect the physics. Experiments with novel laser-driven, high-energy-density plasmas to study the effects on nuclear physics are significantly challenging yet highly important physics. Specifically, new capabilities to generate high fluxes of energetic particles at "short pulse" laser facilities can enable these kinds of physics studies. In this project, we developed and demonstrated a fission diagnostic that can operate in these challenging environments and performed theoretical studies to guide future work.

Mission Impact

Studying nuclear physics at high-energy-density conditions is relevant to LLNL science, yet conducting high-impact experiments requires the development of supporting capabilities. Here we developed a capability to conduct fission experiments at short-pulse laser facilities, which are undergoing rapid growth. Additionally, we conducted theoretical work to guide the future applications of these capabilities for programmatic experiments. A new postdoctoral physicist was hired at the Laboratory.

Publications, Presentations, and Patents

Boller, P. et al. 2020. "First On-Line Detection of Radioactive Fission Isotopes Produced by Laser-Accelerated Protons." Scientific Reports 10, 17183 (2020); doi: 10.1038/s41598-020-74045-5.

Burggraf, J. and A. Zylstra. 2022. "Lasers for the Observation of Multiple Order Nuclear Reactions." Frontiers in Physics 10, 993632 (2022); doi: 10.3389/fphy.2022.993632.

Vogt, R. and J. Randrup. 2021. "Angular Momentum Effects in Fission." Phys. Rev. C 103, 014610 (2021); doi: 10.1103/PhysRevC.103.014610.

Randrup, J. and R. Vogt. 2021. "Generation of Fragment Angular Momentum in Fission." Phys. Rev. Lett. 127, 062502 (2021); doi: 10.1103/PhysRevLett.127.062502.