Eur. Phys. J. A (2025) 61: 45
https://doi.org/10.1140/epja/s10050-025-01512-w

Regular Article - Experimental Physics

A high energy resolution gas target setup to study selected NeNa cycle reactions

¹ Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany
² Università degli Studi di Milano, Via G. Celoria 16, 20133, Milano, Italy
³ INFN, Sezione di Milano, Via G. Celoria 16, 20133, Milano, Italy
⁴ Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy
⁵ Università degli Studi di Genova, Via Dodecaneso 33, 16146, Genova, Italy
⁶ School of Physics and Astronomy, University of Edinburgh, EH9 3FD, Edinburgh, UK
⁷ Dipartimento di Fisica “E. Pancini”, Università degli Studi di Napoli “Federico II”, Via Cintia, 80126, Napoli, Italy
⁸ INFN, Sezione di Napoli, Via Cintia, 80126, Napoli, Italy
⁹ Università degli Studi di Bari, 70125, Bari, Italy
¹⁰ INFN, Sezione di Bari, 70125, Bari, Italy
¹¹ INFN, Sezione di Padova, Via F. Marzolo 8, 35131, Padova, Italy
¹² Dipartimento di Fisica e Astronomia, Università degli Studi di Padova, Via F. Marzolo 8, 35131, Padova, Italy
¹³ INFN Laboratori Nazionali di Legnaro, Via dell’Università 2, 35020, Legnaro (PD), Italy
¹⁴ INFN, Sezione di Torino, Via P. Giuria 1, 10125, Torino, Italy
¹⁵ Università degli Studi di Torino, Torino, Italy
¹⁶ INFN, Laboratori Nazionali del Gran Sasso (LNGS), Assergi (AQ), Italy
¹⁷ Gran Sasso Science Institute (GSSI), L’Aquila, Italy
¹⁸ HUN-REN Institute for Nuclear Research (HUN-REN ATOMKI), PO Box 51, 4001, Debrecen, Hungary
¹⁹ Institute of Physics, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1., 4032, Debrecen, Hungary
²⁰ INFN, Sezione di Roma, Piazzale A. Moro 2, 00185, Roma, Italy
²¹ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences (CSFK), MTA Centre for Excellence, 1121, Budapest, Hungary
²² INAF-Osservatorio Astronomico d’Abruzzo, 64100, Teramo, Italy

^a francesca.cavanna@to.infn.it
^b zavatare@ge.infn.it

Received: 31 October 2024
Accepted: 11 February 2025
Published online: 8 March 2025

Abstract

The neon-sodium cycle of hydrogen burning occurs in several astrophysical sites, such as asymptotic giant branch stars and novae, affecting the production of neon and sodium isotopes. To enhance the accuracy of predicted nucleosynthesis yields, there is a pressing need for new experimental investigations of the cross sections of the reactions involved in this cycle at energies relevant to astrophysics. The 400 kV accelerator at the Laboratory for Underground Nuclear Astrophysics (LUNA) provides a unique advantage relative to above-ground laboratories thanks to its deep underground location within the Gran Sasso National Laboratory (INFN-LNGS) in Italy. We performed experiments at LUNA on two of the reactions of the NeNa cycle: $_{}^{20}$Ne(p,${\gamma )}^{21}$Na and $_{}^{21}$Ne(p,${\gamma )}^{22}$Na using a high-purity gas target system for isotopically enriched gases coupled with two high-resolution germanium detectors, surrounded by copper and lead shielding to further reduce the natural background at LUNA. We describe the detailed characterization of the experimental setup performed through Monte Carlo simulations, and the method for the precise determination of resonance energies, giving improved values of $E_{\text{r}}$ = 127.3 ± 0.5 keV, 271.4 ± 0.4 keV, 272.3 ± 0.4 keV, 291.5 ± 0.5 keV and 352.6 ± 0.4 keV. Additionally, decay branching ratios for the $E_{\text{x}}$ = 7016.4 keV excited state in $_{}^{22}$Na, and three new transitions ($\text{R}\to 4770$ keV, $\text{R}\to 3059.4$ keV and $\text{R}\to 583.05$ keV) in the $E_{\text{r}}$ = 291.5  keV resonance, are also reported.