Eur. Phys. J. A (2020) 56: 75
https://doi.org/10.1140/epja/s10050-020-00077-0

Special Article - New Tools and Techniques

A new approach to monitor -targets degradation in situ for cross-section measurements at LUNA

¹ Gran Sasso Science Institute, Viale F. Crispi 7, 67100, L’Aquila, Italy
² Istituto Nazionale di Fisica Nucleare Laboratori Nazionali del Gran Sasso (LNGS), Via G. Acitelli 22, 67100, Assergi, Italy
³ Institute for Nuclear Research (Atomki), PO Box 51, Debrecen, 4001, Hungary
⁴ Dipartimento di Fisica “E. Pancini”, Università degli Studi di Napoli “Federico II”, Via Cintia 21, 80126, Naples, Italy
⁵ Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Via Cintia 21, 80126, Naples, Italy
⁶ SUPA, School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, UK
⁷ Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Via E. Orabona 4, 70125, Bari, Italy
⁸ Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany
⁹ Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Via F. Marzolo 8, 35131, Padua, Italy
¹⁰ Università degli Studi di Padova, Via F. Marzolo 8, 35131, Padua, Italy
¹¹ Istituto Nazionale di Fisica Nucleare, Sezione di Genova, Via Dodecaneso 33, 16146, Genoa, Italy
¹² Università degli Studi di Torino, Via P. Giuria 1, 10125, Turin, Italy
¹³ Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, 10125, Turin, Italy
¹⁴ Università degli Studi di Genova, Via Dodecaneso 33, 16146, Genoa, Italy
¹⁵ Dipartimento Interateneo di Fisica, Università degli Studi di Bari, Via G. Amendola 173, 70126, Bari, Italy
¹⁶ Università degli Studi di Milano, Via G. Celoria 16, 20133, Milan, Italy
¹⁷ Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via G. Celoria 16, 20133, Milan, Italy
¹⁸ Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Piazzale A. Moro 2, 00185, Rome, Italy
¹⁹ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklós út 15-17, Budapest, 1121, Hungary
²⁰ Politecnico di Bari, Dipartimento Interateneo di Fisica, Via G. Amendola 173, 70126, Bari, Italy
²¹ Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Zellescher Weg 19, 01069, Dresden, Germany
²² INAF Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini, 64100, Teramo, Italy
²³ Dipartimento di Matematica e Fisica, Università degli Studi della Campania L. Vanvitelli, Via Lincoln 5, 81100, Caserta, Italy
²⁴ Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, Via Arnesano, 73100, Lecce, Italy
²⁵ Present address: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116, Brunswick, Germany

^* e-mail: giovanni.ciani@lngs.infn.it
^** e-mail: laszlo.csedreki@lngs.infn.it

Received: 4 October 2019
Accepted: 21 January 2020
Published online: 3 March 2020

Abstract

Direct measurements of reaction cross-sections at astrophysical energies often require the use of solid targets able to withstand high ion beam currents for extended periods of time. Thus, monitoring target thickness, isotopic composition, and target stoichiometry during data taking is critical to account for possible target modifications and to reduce uncertainties in the final cross-section results. A common technique used for these purposes is the Nuclear Resonant Reaction Analysis (NRRA), which however requires that a narrow resonance be available inside the dynamic range of the accelerator used. In cases when this is not possible, as for example the reaction recently studied at low energies at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Italy, alternative approaches must be found. Here, we present a new application of the shape analysis of primary rays emitted by the radiative capture reaction. This approach was used to monitor target degradation in situ during the data taking campaign. The results obtained are in agreement with evaluations subsequently performed at Atomki (Hungary) using the NRRA method. A preliminary application for the extraction of the reaction cross-section at one beam energy is also reported.