Underground nuclear astrophysics: why and how

TL;DR

Underground nuclear astrophysics aims to measure extremely low reaction cross sections by reducing cosmic ray background through underground laboratories, enabling more accurate stellar process studies.

Contribution

This paper reviews the technological advancements and experimental setups used in underground nuclear astrophysics, highlighting the pioneering work of the LUNA project.

Findings

Successful reduction of background noise in underground settings

Development of specialized accelerators and target technologies

Enhanced ability to measure stellar-relevant nuclear reaction cross sections

Abstract

The goal of nuclear astrophysics is to measure cross sections of nuclear physics reactions of interest in astrophysics. At stars temperatures, these cross sections are very low due to the suppression of the Coulomb barrier. Cosmic ray induced background can seriously limit the determination of reaction cross sections at energies relevant to astrophysical processes and experimental setups should be arranged in order to improve the signal-to-noise ratio. Placing experiments in underground sites, however, reduces this background opening the way towards ultra low cross section determination. LUNA (Laboratory for Underground Nuclear Astrophysics) was pioneer in this sense. Two accelerators were mounted at the INFN National Laboratories of Gran Sasso (LNGS) allowing to study nuclear reactions close to stellar energies. A summary of the relevant technology used, including accelerators, target production and characterisation, and background treatment is given.