Study of the 6.05 MeV cascade transition in [inline image]

• Published in: Physics letters. B 2011-09, Vol.703 (5), p.557-561
• Main Authors: Schuermann, D, Di Leva, A, Gialanella, L, Kunz, R, Strieder, F, De Cesare, N, De Cesare, M, D'Onofrio, A, tak, K, Imbriani, G, Rogalla, D, Romano, M, Terrasi, F
• Format: Article
• Language: English
• Subjects: Arrays; Capture (nuclear); Cascades; Combustion; Detectors; Extrapolation; Image contrast
• ISSN: 0370-2693
• DOI: 10.1016/j.physletb.2011.08.061

The radiative capture reaction [inline image] has been investigated in the energy range E=3.3 to 4.5 MeV. This experiment focused in particular on the cascade transition to the 0 super(+ state at E) sub(x)=6.05 MeV in super(16O and was performed by detecting the capture [gamma]-rays with a NaI detector array at the windowless ) super(4)He gas target of the recoil mass separator ERNA in coincidence with the super(16O ejectiles. The 6.05 MeV transition has been considered recently as a component accounting for up to 15% of the [inline image] total cross section at astrophysical energies. The arrangement of the detector array yielded additional information on the [gamma]-ray multipolarity, i.e. the ratio [sigma]) sub(E)2/[sigma] sub(E1, and it was found that the 6.05 MeV transition is entirely E2 in the studied energy range. The results for this transition are analyzed in an R-matrix formalism and extrapolated to the relevant Gamow energy of stellar helium burning, E) sub(0)[similar, equals]300 keV. In contrast to a previous analysis, the present extrapolation suggests a negligible contribution from this amplitude, [inline image]. Additional data for cascade transitions to excited states at E sub(x=6.13, 6.92, and 7.12 MeV, respectively, as well as to the ground state were obtained and the corresponding S factors in the studied energy range are given.)