The PANDORA project: an experimental setup for measuring in-plasma β-decays of astrophysical interest

D Mascali ,Gianluigi Cosentino,S Gammino ,E Naselli ,G Castro ,M Mazzaglia ,A Galatà ,F Odorici ,D Santonocito ,M Maggiore ,C Massimi ,P Finocchiaro ,L Celona ,S Amaducci ,A Mengoni ,G S Mauro ,S Cristallo ,M Busso ,S Palmerini ,G Torrisi

doi:10.1051/epjconf/202022701013

Abstract

Experiments performed on Storage Rings have shown that lifetimes of beta-radionuclides can change dramatically as a function of theionization state. PANDORA (Plasmas for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry) aims at measuring, for the first time, nuclear β-decay rates in stellar-like conditions, especially for radionuclides involved in nuclear-astrophysics processes (BBN, s- processing, CosmoChronometers, Early Solar System formation). Compact magnetic plasma traps, where plasmas reach density ne~10n-1014 cm-3, and temperature Te~0.1-30 keV, are suitable for such studies. The decay rates can be measured as a function of the charge state distribution of the inplasma ions. The collaboration is now designing the plasma trap able to reach the needed plasma densities, temperatures and charge states distributions. A first list of radioisotopes, including tens of physics cases of potential interest is now available. Possible physics cases include, among the others, 2°4Tl, 63Ni, 6°Co, 171Tm, 147Pm, 85Kr, 176Lu and the pairs 187Re-187Os and 87Sr-87Rb, which play a crucial role as cosmo-clock. Physics cases are now under evaluation in terms of lifetime measurements feasibility in a plasma trap.

Highlights

In the last decades, there was a growing interest in Nuclear Astrophysics involving lowenergy heavy-ion reactions and radioactive-decays in astrophysical environment
Terrestrial measurements involve, up to now, neutral species, while both nuclear reactions and decays involved in nuclear astrophysics should be investigated in peculiar plasma environments
In order to estimate the detailed nucleosynthetic consequences of “slow” neutron fluxes occurring in various phases of stellar evolution, one would want to know the halflives of all the radioactive nuclei sited at possible branching points along the n-capture path, in thermal conditions spanning the range from 8keV (the energy at which neutrons are released by the 13C(α,n)16O reaction in low mass AGB stars [3, 4]) to above 90 keV (the typical thermal energy of C-burning shell phases in massive-star evolution [5]; in this last environment, the isotope 22Ne, remaining after core He burning, can generate bursts of neutrons through the 22Ne(α,n)25Mg reaction [6, 7])

Summary

Introduction

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Results

Conclusion