Eur. Phys. J. A (2018) 54: 44
https://doi.org/10.1140/epja/i2018-12476-7

Regular Article - Experimental Physics

A high-efficiency gas target setup for underground experiments, and redetermination of the branching ratio of the 189.5 keV ²²Ne(p,)²³Na resonance

¹ Dipartimento di Fisica, Università degli Studi di Genova, Genova, Italy
² INFN, Sezione di Genova, Genova, Italy
³ Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, Germany
⁴ Technische Universität Dresden, Dresden, Germany
⁵ INFN, Sezione di Padova, Padova, Italy
⁶ Dipartimento di Fisica e Astronomia, Università di Padova, Padova, Italy
⁷ Dipartimento Interateneo di Fisica “Michelangelo Merlin”, Università degli Studi di Bari, Bari, Italy
⁸ INFN, Sezione di Bari, Bari, Italy
⁹ SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK
¹⁰ Dipartimento di Fisica “E. Pancini”, Università di Napoli Federico II and INFN, Sezione di Napoli, Strada Comunale Cinthia, 80126, Napoli, Italy
¹¹ Gran Sasso Science Institute, L’Aquila, Italy
¹² INFN, Laboratori Nazionali del Gran Sasso, Assergi, Italy
¹³ Institute of Nuclear Research (MTA Atomki), Debrecen, Hungary
¹⁴ Dipartimento di Fisica, Università di Torino, and INFN Sezione di Torino, Torino, Italy
¹⁵ Università degli Studi di Milano and INFN, Sezione di Milano, Milano, Italy
¹⁶ INFN, Sezione di Roma “La Sapienza”, Roma, Italy
¹⁷ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121, Budapest, Hungary
¹⁸ Dipartimento di Fisica “E. Fermi”, Università di Pisa, and INFN, Sezione di Pisa, Pisa, Italy
¹⁹ INAF Osservatorio Astronomico di Teramo, Via Mentore Maggini, 64100, Teramo, Italy

^* e-mail: caciolli@pd.infn.it

Received: 3 November 2017
Accepted: 10 February 2018
Published online: 15 March 2018

Abstract

The experimental study of nuclear reactions of astrophysical interest is greatly facilitated by a low-background, high-luminosity setup. The Laboratory for Underground Nuclear Astrophysics (LUNA) 400kV accelerator offers ultra-low cosmic-ray induced background due to its location deep underground in the Gran Sasso National Laboratory (INFN-LNGS), Italy, and high intensity, 250-500μA, proton and ion beams. In order to fully exploit these features, a high-purity, recirculating gas target system for isotopically enriched gases is coupled to a high-efficiency, six-fold optically segmented bismuth germanate (BGO) -ray detector. The beam intensity is measured with a beam calorimeter with constant temperature gradient. Pressure and temperature measurements have been carried out at several positions along the beam path, and the resultant gas density profile has been determined. Calibrated -intensity standards and the well-known keV ¹⁴N(p,)¹⁵O resonance were used to determine the -ray detection efficiency and to validate the simulation of the target and detector setup. As an example, the recently measured resonance at keV in the ²²Ne(p,)²³Na reaction has been investigated with high statistics, and the -decay branching ratios of the resonance have been determined.