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

Title: Underground studies of pp and CNO

Abstract

Cross section measurements for quiescent stellar H and He burning are hampered mainly by extremely low counting rate and cosmic background. Some of the main reactions of H-burning phase have been measured at the LUNA facility (Laboratory for Underground Nuclear Astrophysics) taking advantage of the very low background environment of the Underground Gran Sasso National Laboratory in Italy. An overview of the adopted experimental techniques is given together with the latest results on the 14N(p,{gamma})15O reaction and the status of the ongoing 3He(4He,{gamma})7Be experiment.

Authors:
 [1];  [2]
  1. INFN Genova (Italy)
  2. (US))
Publication Date:
OSTI Identifier:
21056754
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 891; Journal Issue: 1; Conference: 6. Symposium on nuclear physics, Tours (France), 5-8 Sep 2006; Other Information: DOI: 10.1063/1.2713530; (c) 2007 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; ALPHA REACTIONS; ASTROPHYSICS; BERYLLIUM 7; CAPTURE; COUNTING RATES; CROSS SECTIONS; HELIUM 3 TARGET; HELIUM 4; HELIUM BURNING; HYDROGEN BURNING; ITALY; NITROGEN 14 TARGET; NUCLEOSYNTHESIS; OXYGEN 15; PROTON REACTIONS; PROTONS

Citation Formats

Costantini, Heide, and University of Notre Dame, IN. Underground studies of pp and CNO. United States: N. p., 2007. Web. doi:10.1063/1.2713530.
Costantini, Heide, & University of Notre Dame, IN. Underground studies of pp and CNO. United States. doi:10.1063/1.2713530.
Costantini, Heide, and University of Notre Dame, IN. Mon . "Underground studies of pp and CNO". United States. doi:10.1063/1.2713530.
@article{osti_21056754,
title = {Underground studies of pp and CNO},
author = {Costantini, Heide and University of Notre Dame, IN},
abstractNote = {Cross section measurements for quiescent stellar H and He burning are hampered mainly by extremely low counting rate and cosmic background. Some of the main reactions of H-burning phase have been measured at the LUNA facility (Laboratory for Underground Nuclear Astrophysics) taking advantage of the very low background environment of the Underground Gran Sasso National Laboratory in Italy. An overview of the adopted experimental techniques is given together with the latest results on the 14N(p,{gamma})15O reaction and the status of the ongoing 3He(4He,{gamma})7Be experiment.},
doi = {10.1063/1.2713530},
journal = {AIP Conference Proceedings},
number = 1,
volume = 891,
place = {United States},
year = {Mon Feb 26 00:00:00 EST 2007},
month = {Mon Feb 26 00:00:00 EST 2007}
}
  • The available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production are summarized and critically evaluated. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for 8B solar neutrinos. Opportunities for further increasing the precision of key rates are also discussed, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplement tomore » 1998, Rev. Mod. Phys. 70, 1265.« less
  • The available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production are summarized and critically evaluated. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for {sup 8}B solar neutrinos. Opportunities for further increasing the precision of key rates are also discussed, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplementmore » to 1998, Rev. Mod. Phys. 70, 1265.« less
  • We determined the total reaction rate of the {sup 11}C({alpha},p){sup 14}N reaction relevant to the nucleosynthesis in explosive hydrogen-burning stars. The measurement was performed by means of the thick target method in inverse kinematics with {sup 11}C RI beams. We performed the identification of the ground-state transition and excited-state transitions using time-of-flight information for the first time.
  • Borexino is an experiment for low-energy neutrino spectroscopy at the Gran Sasso underground laboratories. It is designed to measure the monoenergetic {sup 7}Be solar neutrino flux in real time, via neutrino-electron elastic scattering in an ultrapure organic liquid scintillator. Borexino has the potential to also detect neutrinos from the pep fusion process and the CNO cycle. For this measurement to be possible, radioactive contamination in the detector must be kept extremely low. Once sufficiently clean conditions are met, the main background source is {sup 11}C, produced in reactions induced by the residual cosmic muon flux on {sup 12}C. In themore » process, a free neutron is almost always produced. {sup 11}C can be tagged on an event-by-event basis by looking at the threefold coincidence with the parent muon track and the subsequent neutron capture on protons. This coincidence method has been implemented on the Borexino Counting Test Facility data. We report on the first event-by-event identification of in situ muon-induced {sup 11}C in a large underground scintillator detector. We measure a {sup 11}C production rate of 0.130 {+-} 0.026(stat) {+-} 0.014(syst) day{sup -1} ton{sup -1}, in agreement with predictions from both experimental studies performed with a muon beam on a scintillator target and ab initio estimations based on the {sup 11}C producing nuclear reactions.« less
  • We report on an investigation into the consequences of thermonuclear runaways in 10/sup -4/ M/sub sun/ accreted hydrogen envelopes on 1.00 M/sub sun/ white dwarfs. These evolutionary sequences predict that from 10/sup -5/ M/sub sun/ to 5 x 10/sup -5/ M/sub sun/ will be ejected with speeds from 300 to 3800 km s/sup -1/ (kinetic energies of 10/sup 44/-10/sup 45/ ergs). Absolute visual magnitudes as high as -8.1 mag are attained, well within the observed range for fast novae. In addition, the shapes of the theoretical light curves are more reminiscent of an observed fast nova light curve than thosemore » in our earlier studies.The ejected material is stongly enhanced in the products of incomplete CNO burning: the most abundant of the ejected nuclei is /sup 1/3C, followed by /sup 14/N and /sup 12/C. The differences from previous studies are attributable to the lower peak temperatures reached in these sequences. These models also produce a large (approx.200) overabundance of /sup 7/Li, suggesting that novae may represent significant contributors to the galactic enrichment of this nucleus.We discuss the effects of circumbinary material on the light curve. We suggest that the presence of this gas, the remnant of nonconservative mass transfer, can strongly affect the shape of the light curve around maximum visual magnitude in an actual nova outburst.We find, as in our earlier work, that these models do not eject their entire accreted envelopes in the earliest stages of the outburst. The residual envelopes quickly evolve to configurations which are hot and bright, representing the probable source for the UV radiation observed in all recent classical novae.« less