E1 and E2 S factors of {sup 12}C({alpha},{gamma}{sub 0}){sup 16}O from {gamma}-ray angular distributions with a 4 {pi}-detector array

Journal Article · Mon May 15 00:00:00 EDT 2006 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.73.055801· OSTI ID:20771559

Assuncao, M; Lefebvre-Schuhl, A; Kiener, J; Tatischeff, V; Boukari-Pelissie, C; Coc, A; Correia, J J; Grama, C; Hannachi, F; Korichi, A; LeDu, D; Lopez-Martens, A; Meunier, R; Thibaud, J P ^[1]; Fey, M; Hammer, J W; Kunz, R; Malcherek, D ^[2]; Beck, C; Courtin, S ^[3]

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1. Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse (CSNSM), UMR8609, CNRS/IN2P3, Universite Paris-Sud, F-91405 Orsay-Campus (France)
2. Institut fuer Strahlenphysik (IfS), Universitaet Stuttgart, D-70550 Stuttgart (Germany)
3. Institut Pluridisciplinaire Hubert Curien (IPHC), UMR7178, Departement de Recherches Subatomiques, CNRS/IN2P3, Universite Louis Pasteur - Strasbourg I, 23 rue du Loess, B.P. 28, F-67037 Strasbourg Cedex, 2 (France)

A new experiment to determine the thermonuclear cross section of the {sup 12}C({alpha},{gamma}){sup 16}O reaction has been performed in regular kinematics using an intense {alpha}-particle beam of up to 340 {mu}A from the Stuttgart DYNAMITRON. For the first time, a 4{pi}-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 nine EUROGAM high-purity Ge detectors in close geometry, actively shielded individually with bismuth germanate crystals. The {sup 12}C targets were isotopically enriched by magnetic separation during implantation. The depth profiles of the implanted carbon in the {sup 12}C targets were 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 {sup 16}O ground state were measured in the energy range E{sub c.m.}=1.30-2.78 MeV and in the angular range (lab.) 30 deg. -130 deg. . From these distributions, astrophysical E1 and E2 S-factor functions vs energy were calculated, both of which are indispensable to the modeling of this reaction and the extrapolation toward lower energies. The separation of the E1 and E2 capture channels was done both by taking the phase value {phi}{sub 12} as a free parameter and by fixing it using the results of elastic {alpha}-particle scattering on {sup 12}C in the same energy range.

• OSTI ID: 20771559
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 73, Issue 5; Other Information: DOI: 10.1103/PhysRevC.73.055801; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA PARTICLES
ALPHA REACTIONS
ANGULAR DISTRIBUTION
BGO DETECTORS
CARBON 12
CARBON 12 TARGET
CROSS SECTIONS
DYNAMITRONS
ENERGY-LEVEL TRANSITIONS
EXTRAPOLATION
GAMMA DECAY
GAMMA RADIATION
GROUND STATES
HIGH-PURITY GE DETECTORS
OXYGEN 16
RUTHERFORD BACKSCATTERING SPECTROSCOPY
SCATTERING
SIMULATION