2023 Impact factor 2.6
Hadrons and Nuclei
Eur. Phys. J. A 6, 451-461

The E1 and E2 capture amplitudes in 12C($\alpha$,$\gamma_0$)16O

G. Roters - C. Rolfs - F. Strieder - H.P. Trautvetter

Institut für Physik mit Ionenstrahlen, Ruhr-Universität Bochum, Bochum, Germany

Received: 23 August 1999 Communicated by B. Povh

Excitation functions of the $\gamma_o$ capture transition in 12C( $\alpha,\gamma$)16O at $\theta_{\gamma} = 90^{\circ}$ were obtained using a $4 \times 4''$ BGO crystal in close geometry (E = 0.94 to 3.39 MeV) and a $2 \times 2''$ BGO crystal in far geometry (E = 1.69 to 3.29 MeV), where the study of the reaction was initiated in inverse kinematics involving a windowless gas target. The small crystal detected essentially the E1 multipole component in the $\gamma_0$ capture transition, while the large crystal observed approximately the angle-integrated sum of the E1 and E2 multipole components. Analysis of the two data sets together with data from previous work provided strong evidence that both multipoles are of equal importance at the relevant stellar energy E0 = 0.3 MeV.

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