Probing key 19F(p, γ)20Ne resonances with innovative targets at LUNA

by Dr Ricardo Biassissi (DFA)

Thursday 11 Dec 2025, 14:00 → 14:15 Europe/Rome

1/1-3 - Aula B (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

The thermonuclear reaction 19F(p, γ)20Ne represents a potential breakout path from the CNO cycle
during hydrogen burning under extreme conditions. This reaction is particularly relevant
for Population III stars, where a significant rate enhancement at T ≈ 0.1GK could trigger nucleosynthesis
beyond fluorine and contribute to calcium enrichment observed in the most metal-poor
stars.
The measurement is being carried out at the Laboratory for Underground Nuclear Astrophysics
(LUNA) at Gran Sasso National Laboratories, where the ultra-low background environment enables
detection of rare signals at astrophysically relevant energies. Using the 400 kV accelerator,
we are investigating the energy region Ecm = 190−390 keV, covering key resonances at 213, 225,
and 323 keV. The recently discovered 225 keV resonance, for which only upper limits exist, dominates
the rate uncertainty at stellar temperatures. To minimize systematic uncertainties, various
types of 19F-targets have been employed, including a novel chemically fluorinated target developed
specifically for this experiment. Gamma rays are detected with a high-efficiency BGO array
covering nearly 4π solid angle.