skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Recent results at LUNA, using a solid target

Abstract

The determination of the astrophysical S-factor of the 14N(p,{gamma})15O reaction is of great interest because this reaction represents the bottleneck of the CNO cycle, which in turn has a large influence on the determination of the age of globular clusters and also plays a role in the estimation of the Solar neutrino fluxes. We have performed a new underground measurement (LUNA, Gran Sasso Laboratory, Italy) using a high resolution set-up, extending the investigated energy range down to Ecm=130 keV. This allowed a more reliable extrapolation to astrophysical energies, using an R-matrix fit to the decay to different final states in 15O.

Authors:
 [1];  [2];  [3];  [4];  [2]
  1. Universita di Napoli 'Federico II', Dipartimento di Fisica, Naples (Italy)
  2. (Italy)
  3. Laboratori Nazionali del Gran Sasso dell INFN, Assergi (Italy)
  4. Universita di Genova, Dipartimento di Fisica, Genova (Italy)
Publication Date:
OSTI Identifier:
20798596
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 831; Journal Issue: 1; Conference: International conference on frontiers in nuclear structure, astrophysics, and reactions - FINUSTAR, Isle of Kos (Greece), 12-17 Sep 2005; Other Information: DOI: 10.1063/1.2200984; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; CAPTURE; CNO CYCLE; COSMIC NEUTRINOS; EXTRAPOLATION; ITALY; KEV RANGE; NITROGEN 14; NUCLEAR DECAY; OXYGEN 15; PROTONS; R MATRIX; RESOLUTION; SOLAR NEUTRINOS; SPECTROSCOPIC FACTORS; UNDERGROUND

Citation Formats

Imbriani, G., INFN, Naples, Formicola, A., Costantini, H., and INFN, Genova. Recent results at LUNA, using a solid target. United States: N. p., 2006. Web. doi:10.1063/1.2200984.
Imbriani, G., INFN, Naples, Formicola, A., Costantini, H., & INFN, Genova. Recent results at LUNA, using a solid target. United States. doi:10.1063/1.2200984.
Imbriani, G., INFN, Naples, Formicola, A., Costantini, H., and INFN, Genova. Wed . "Recent results at LUNA, using a solid target". United States. doi:10.1063/1.2200984.
@article{osti_20798596,
title = {Recent results at LUNA, using a solid target},
author = {Imbriani, G. and INFN, Naples and Formicola, A. and Costantini, H. and INFN, Genova},
abstractNote = {The determination of the astrophysical S-factor of the 14N(p,{gamma})15O reaction is of great interest because this reaction represents the bottleneck of the CNO cycle, which in turn has a large influence on the determination of the age of globular clusters and also plays a role in the estimation of the Solar neutrino fluxes. We have performed a new underground measurement (LUNA, Gran Sasso Laboratory, Italy) using a high resolution set-up, extending the investigated energy range down to Ecm=130 keV. This allowed a more reliable extrapolation to astrophysical energies, using an R-matrix fit to the decay to different final states in 15O.},
doi = {10.1063/1.2200984},
journal = {AIP Conference Proceedings},
number = 1,
volume = 831,
place = {United States},
year = {Wed Apr 26 00:00:00 EDT 2006},
month = {Wed Apr 26 00:00:00 EDT 2006}
}
  • The case of the most recent measurement performed at LUNA, the {sup 15}N(p,gamma){sup 16}O reaction, is presented. This reaction, together with the {sup 15}N(p,alpha){sup 12}C, forms the branching point from the first to the second CNO cycle and the ratio of their respective reaction rates influences the nucleosynthesis yields of {sup 16}O, {sup 17}O e {sup 17}F. In particular, one of the three different campaigns performed by the LUNA collaboration to measure the cross section of this reaction will be discussed. This experiment was performed by impinging a proton beam from the LUNA accelerator with energies ranging from 77 tomore » 350 keV in the centre-of-mass reference frame on a TiN solid target, enriched in {sup 15}N to 98%. The gamma-rays following the (p, gamma) reaction were detected by means of an high-efficiency BGO detector.« less
  • 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
  • The {sup 15}N(p,gamma){sup 16}O reaction links the CN cycle to the NO cycle allowing for the production of the oxygen and fluorine isotopes during the hydrogen burning in novae and AGB stars. This reaction has been intensively studied by the LUNA collaboration.In this contribution the experiment performed using a BGO detector and a windowless gas target setup is described. The measurement of the astrophysical S-factor has been done in the center of mass energy range from 90 keV to 230 keV. The cross section is found to be a factor two lower than previously believed.