An excitation function of the ground-state gamma (0)-ray capture transition in C-12(alpha, gamma)O-16 at theta (gamma) = 90 degrees 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 El capture amplitude. The data at E = 1.32 to 2.99 MeV lead to an extrapolated astrophysical S factor S-E1(E-0) = 90 +/- 15 keV b at E-0 = 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 S-E1(E-0) value. As a consequence, the case of destructive interference between the two lowest E1 sources with S-E1(E-0) = 8 +/- 3 keV b cannot be ruled out rigorously.
The E1 capture amplitude in 12C(α,γ0) 16O / L., G., D., R., F., S., S., T., G., G., C., A., R., A., M., A., L., C., A., D.Z., A., D., P., F., U., G., Imbriani, G., A., O., Roca, V., C., R., Romano, M., C., S., P., S., et al.. - In: THE EUROPEAN PHYSICAL JOURNAL. A, HADRONS AND NUCLEI. - ISSN 1434-6001. - STAMPA. - 11:3(2001), pp. 357-370. [10.1007/s100500170075]
The E1 capture amplitude in 12C(α,γ0) 16O
IMBRIANI, GIANLUCA;ROCA, VINCENZO;ROMANO, MARIO;
2001
Abstract
An excitation function of the ground-state gamma (0)-ray capture transition in C-12(alpha, gamma)O-16 at theta (gamma) = 90 degrees 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 El capture amplitude. The data at E = 1.32 to 2.99 MeV lead to an extrapolated astrophysical S factor S-E1(E-0) = 90 +/- 15 keV b at E-0 = 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 S-E1(E-0) value. As a consequence, the case of destructive interference between the two lowest E1 sources with S-E1(E-0) = 8 +/- 3 keV b cannot be ruled out rigorously.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
