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Title: Experiences and prospects of nuclear astrophysics in underground laboratories

Abstract

Impressive progress has been made in the course the last decades in understanding astrophysical objects. Increasing precision of nuclear physics data has contributed significantly to this success, but now a better understanding of several important findings is frequently limited by uncertainties related to the available nuclear physics data. Consequently it is desirable to improve significantly the quality of these data. An important step towards higher precision is an excellent signal to background ratio of the data. Placing an accelerator facility inside an underground laboratory reducing the cosmic ray induced background by six orders of magnitude is a powerful method to reach this goal, even though careful reduction of environmental and beam induced background must still be considered. Experience in the field of underground nuclear astrophysics has been gained since 20 years due to the pioneering work of the LUNA Collaboration (Laboratory for Underground Nuclear Astrophysics) operating inside the underground laboratories of the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. Based on the success of this work presently also several other projects for underground laboratories dedicated to nuclear astrophysics are being pursued worldwide. This contribution will give a survey of the past experience in underground nuclear astrophysics as well asmore » an outlook on future developments.« less

Authors:
 [1]
  1. INFN - Laboratori Nazionali del Gran Sasso, Via Acitelli, 22, 67100 L'Aquila, Località Assergi (Italy)
Publication Date:
OSTI Identifier:
22280378
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1595; Journal Issue: 1; Conference: 7. European summer school on experimental nuclear astrophysics, Santa Tecla, Sicily (Italy), 15-17 Sep 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACCELERATOR FACILITIES; ACCURACY; ASTROPHYSICS; BACKGROUND RADIATION; COSMIC RADIATION; ITALY; NUCLEAR REACTIONS; UNDERGROUND

Citation Formats

Junker, M. Experiences and prospects of nuclear astrophysics in underground laboratories. United States: N. p., 2014. Web. doi:10.1063/1.4875300.
Junker, M. Experiences and prospects of nuclear astrophysics in underground laboratories. United States. doi:10.1063/1.4875300.
Junker, M. Fri . "Experiences and prospects of nuclear astrophysics in underground laboratories". United States. doi:10.1063/1.4875300.
@article{osti_22280378,
title = {Experiences and prospects of nuclear astrophysics in underground laboratories},
author = {Junker, M.},
abstractNote = {Impressive progress has been made in the course the last decades in understanding astrophysical objects. Increasing precision of nuclear physics data has contributed significantly to this success, but now a better understanding of several important findings is frequently limited by uncertainties related to the available nuclear physics data. Consequently it is desirable to improve significantly the quality of these data. An important step towards higher precision is an excellent signal to background ratio of the data. Placing an accelerator facility inside an underground laboratory reducing the cosmic ray induced background by six orders of magnitude is a powerful method to reach this goal, even though careful reduction of environmental and beam induced background must still be considered. Experience in the field of underground nuclear astrophysics has been gained since 20 years due to the pioneering work of the LUNA Collaboration (Laboratory for Underground Nuclear Astrophysics) operating inside the underground laboratories of the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. Based on the success of this work presently also several other projects for underground laboratories dedicated to nuclear astrophysics are being pursued worldwide. This contribution will give a survey of the past experience in underground nuclear astrophysics as well as an outlook on future developments.},
doi = {10.1063/1.4875300},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1595,
place = {United States},
year = {Fri May 09 00:00:00 EDT 2014},
month = {Fri May 09 00:00:00 EDT 2014}
}
  • It is known that the chemical elements and their isotopes were created by nuclear fusion reactions in the hot interiors of remote and long-vanished stars over many billions of years. The present picture is that all elements from carbon to uranium have been produced entirely within stars during their fiery lifetimes and explosive deaths. The detailed understanding of the origin of the chemical elements and their isotopes combines astrophysics and nuclear physics, and forms what is called nuclear astrophysics. In turn, nuclear reactions are at the heart of nuclear astrophysics: they influence sensitively the nucleosynthesis of the elements in themore » earliest stages of the universe and in all the objects formed thereafter, and control the associated energy generation, neutrino luminosity, and evolution of stars. A good knowledge of the rates of these fusion reactions is essential to understanding this broad picture. Some of the most important experimental techniques to measure the corresponding cross sections, based both on direct and indirect methods, will be described in this paper.« less
  • LUNA, Laboratory for Underground Nuclear Astrophysics at Gran Sasso, is studying thermonuclear reactions down to the energy of the nucleosynthesis inside stars. Significant results, relevant for neutrino physics, have been the measurements of the 3He(3He,2p)4He cross section within the Gamow peak of the Sun and of 14N(p,{gamma})15O down to very low energy. The results will be discussed together with the status of the running experiment on 3He({alpha}, {gamma})7Be.
  • Nuclear cross sections play a key role in understanding stellar evolution and elemental synthesis. Also in the field of astroparticle physics precise knowledge on thermonuclear cross sections is needed to extract the particle properties from the experimental data. While it is desirable to directly measure the relevant cross sections in the energy range of interest for the specific stellar environment this proves to be difficult, if not impossible, due to the effect of the Coulomb barrier, which causes an exponential drop of the cross sections at stellar energies. Consequently direct measurements are hampered by low counting rates and background causedmore » by cosmic rays and environmental radioactivity. In addition background induced by the beam or the target itself can disturb the measurements.In this contribution I will discuss some of the reactions studied by LUNA in the past years to illustrate important aspects underground nuclear astrophysics.« less
  • DIANA (Dakota Ion Accelerator for Nuclear Astrophysics) is a proposed facility designed to be operated deep underground. The DIANA collaboration includes nuclear astrophysics groups from Lawrence Berkeley National Laboratory, Michigan State University, Western Michigan University, Colorado School of Mines, and the University of North Carolina, and is led by the University of Notre Dame. The scientific goals of the facility are measurements of low energy nuclear cross-sections associated with sun and pre-supernova stars in a laboratory setup at energies that are close to those in stars. Because of the low stellar temperatures associated with these environments, and the high Coulombmore » barrier, the reaction cross-sections are extremely low. Therefore these measurements are hampered by small signal to background ratios. By going underground the background due to cosmic rays can be reduced by several orders of magnitude. We report on the design status of the DIANA facility with focus on the 3 MV electrostatic accelerator.« less
  • Underground nuclear astrophysics with LUNA at the Laboratori Nazionali del Gran Sasso spans a history of 20 years. By using the rock overburden of the Gran Sasso mountain chain as a natural cosmic-ray shield very low signal rates compared to an experiment on the surface can be tolerated. The cross sectons of important astrophysical reactions directly in the stellar energy range have been successfully measured. In this proceeding we give an overview over the key accomplishments of the experiment and an outlook on its future with the expected addition of an additional accelerator to the underground facilities, enabling the coveragemore » of a wider energy range and the measurement of previously inaccessible reactions.« less