E1- and E2-S of 12 alpha,gamma 0 16 O from gamma-ray angular distributions with a 4pi detector array
ASSUNCAO, M.
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Instituto de Física [IDF]
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Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Instituto de Física [IDF]
ASSUNCAO, M.
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Instituto de Física [IDF]
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Instituto de Física [IDF]
HAMMACHE, F.
Gesellschaft für Schwerionenforschung [GSI]
Institut de Physique Nucléaire d'Orsay [IPNO]
Gesellschaft für Schwerionenforschung [GSI]
Institut de Physique Nucléaire d'Orsay [IPNO]
HANNACHI, F.
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Centre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG]
< Réduire
Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse [CSNSM]
Centre d'Etudes Nucléaires de Bordeaux Gradignan [CENBG]
Langue
en
Article de revue
Ce document a été publié dans
Physical Review C. 2006, vol. 73, p. 055801-19
American Physical Society
Résumé en anglais
A new experiment to determine the thermonuclear cross section of the 12C(alpha,gamma_0)16O reaction has been performed in regular kinematics using an intense alpha-particle beam of up to 340 muA from the Stuttgart DYNAMITRON. ...Lire la suite >
A new experiment to determine the thermonuclear cross section of the 12C(alpha,gamma_0)16O reaction has been performed in regular kinematics using an intense alpha-particle beam of up to 340 muA from the Stuttgart DYNAMITRON. For the first time a 4pi-Germanium-detector setup has been used to measure the angular distribution of the gamma rays at all angles simultaneously. It consisted of an array of 9 EUROGAM HPGe detectors in close geometry, actively shielded individually with BGO crystals. The 12C targets were isotopically enriched by magnetic separation during implantation. The depth profiles of the implanted carbon in the 12C targets have been determined by Rutherford backscattering for purposes of cross section normalization and absolute determination of the E1 and E2 S factors. Angular distributions of the gamma decay to the 16O ground state have been measured in the energy range E_c.m.= 1.30-2.78 MeV and in the angular range (lab.) 30-130 degre. From these distributions, astrophysical E1 and E2 S-factor functions vs. energy have been calculated, both of which are indispensable for the modeling of this reaction and the extrapolation towards lower energies. The separation of the E1 and E2 capture channels has been done both by taking the phase value phi_12 as a free parameter and by fixing it using the results of elastic alpha-particle scattering on 12C in the same energy range.< Réduire
Mots clés en anglais
nuclear astrophysics
cross-section measurements
12C(alpha
gamma)16O
thermonuclear stellar burning
E1 S factor
E2 S factor
4pi gamma Germainum array
gamma angular distributions
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