Laser-based approach to measure small nuclear cross sections in plasma.

We demonstrate an approach successfully measuring very small nuclear isomeric excitation cross sections (on the order of 10 to 100 picobarns) via laser-cluster interaction. The interaction between an intense laser pulse and Kr atomic clusters generates a high-temperature and high-density plasma ball in which nuclear excitations are facilitated by inelastic electron scattering. The electron temperature reaches several hundred keV (corresponding to 10[Formula: see text] K), similar to a stellar environment. The very small nuclear excitation cross sections are extremely challenging to measure otherwise, for example using traditional accelerator-based approaches. Our method opens a broad avenue of measuring small nuclear cross sections and holds promise for advancing understanding of nuclear transition mechanisms and exploring pathways in the evolutionary dynamics of elements within stellar environments.