2019 Impact factor 2.176
Hadrons and Nuclei


Eur. Phys. J. A 11, 357-370 (2001)

The E1 capture amplitude in ${^{12}C(\alpha,\gamma_{0})}{^{16}O}$

L. Gialanella1, D. Rogalla1, F. Strieder1, S. Theis1, G. Gyürki2, C. Agodi3, R. Alba3, M. Aliotta1, L. Campajola4, A. Del Zoppo3, A. D'Onofrio5, P. Figuera3, U. Greife1, G. Imbriani4, A. Ordine4, V. Roca4, C. Rolfs1, M. Romano4, C. Sabbarese5, P. Sapienza3, F. Schümann1, E. Somorjai3, F. Terrasi5 and H.P. Trautvetter1

1  Institut für Physik mit Ionenstrahlen, Ruhr-Universität Bochum, Bochum, Germany
2  Atomki, Debrecen, Hungary
3  Laboratori Nazionali del Sud, INFN, Catania, Italy
4  Dipartimento di Scienze Fisiche, Università Federico II, Napoli and INFN, Napoli, Italy
5  Dipartimento di Scienze Ambientali, Seconda Università di Napoli, Caserta and INFN, Napoli, Italy

rolfs@ep3.ruhr-uni-bochum.de

(Received: 6 June 2001 / Revised version: 9 July 2001 Communicated by Th. Walcher)

Abstract
An excitation function of the ground-state $\gamma_{0}$-ray capture transition in 12C $(\alpha, \gamma)^{16}$O at $\theta_{\gamma} = 90^{\circ}$ was obtained in far geometry using six Ge detectors, where the study of the reaction was initiated in inverse kinematics involving a windowless gas target. The detectors observed predominantly the E1 capture amplitude. The data at E = 1.32 to 2.99 MeV lead to an extrapolated astrophysical S factor $S_{E1}(E_{0}) = 90 \pm 15$ keV b at E0 = 0.3 MeV (for the case of constructive interference between the two lowest E1 sources), in good agreement with previous works. However, a novel Monte Carlo approach in the data extrapolation reveals systematic differences between the various data sets such that a combined analysis of all available data sets could produce a biased estimate of the SE1(E0) value. As a consequence, the case of destructive interference between the two lowest E1 sources with $S_{E1}(E_{0}) = 8\pm 3$ keV b cannot be ruled out rigorously.

PACS
24.10.-i - Nuclear-reaction models and methods.
25.40.-h - Nucleon-induced reactions.

© Società Italiana di Fisica, Springer-Verlag 2001