Speaker
Description
The properties of radioactive nuclei embedded in hot, highly ionized plasmas play a fundamental role in stellar nucleosynthesis. In particular, the ionization state can profoundly modify beta-decay rates through the opening of additional decay channels, such as Bound-State Beta Decay (BSBD), experimentally observed in fully stripped ions stored in heavy-ion storage rings. These effects can alter the lifetime of selected radionuclides by several orders of magnitude, influencing key branching points along the s-process nucleosynthesis path. A major experimental challenge is the investigation of these phenomena under plasma conditions resembling stellar interiors, where ions coexist with free electrons over a broad distribution of charge states. Addressing this challenge is the primary scientific objective of PANDORA (Plasmas for Astrophysics, Nuclear Decays Observation and Radiation for Archaeometry), a new facility under construction at INFN-LNS. PANDORA will exploit a superconducting Electron Cyclotron Resonance magnetic trap to generate stable, magnetically confined plasmas with electron temperatures of several tens of keV and accurately controlled plasma parameters. Within this environment, the decay rates of selected radionuclides — including 94Nb, 176Lu, and 134Cs — will be measured during the first experimental phase (starting from late 2027), as a function of the plasma ionization conditions, providing the first laboratory investigation of beta decay in stellar-like, non-LTE plasmas. A list of more than 110 isotopes is ready for further and future measurements, including 7Be and other radionuclides relevant in astrophysical scenarios. Beyond its physics goals, PANDORA represents a novel experimental platform combining plasma production with advanced non-invasive diagnostics, including high-resolution X-ray spectroscopy, interferometry, polarimetry, and gamma-ray detection. These complementary techniques enable a comprehensive characterization of the plasma environment, allowing nuclear observables to be directly correlated with independently measured plasma parameters. They will also enable the investigation of plasma opacities under stellar-like conditions, providing valuable experimental benchmarks for the interpretation of kilonova light curves and the inference of r-process elemental abundances in the ejecta. This contribution will present the scientific motivations, experimental approach, and diagnostic capabilities that make PANDORA a unique tool for benchmarking models of weak interactions and radiative plasma properties under stellar-like conditions, thereby strengthening the connection between laboratory plasma physics and nuclear astrophysics.