12C(16O,γ)28

Abstract

The heavy-ion radiative capture reaction 12 C(16 O,γ) 28 Si has been studied at three energies E c.m. = 8.5, 8.8, and 9 MeV which are close to the Coulomb barrier. The weak radiative capture process has been identified by measuring the 28 Si recoils in the highly selective 0 • spectrometer DRAGON at TRIUMF (Vancouver). The coincident γ rays have been recorded in the associated BGO array. This has allowed a complete measurement of the γ spectrum and the relative strength of all decay pathways. An important part of the decay through quasibound states close to the particle threshold and the feeding of bound states with particular deformation have been identified for the first time. Comparisons with Monte Carlo simulations allowed the extraction of the full experimental radiative capture cross section. Our results suggest an important contribution of spins J π = 5 − and 6 + in the entrance channel. The surprisingly large cross sections from 12 μb at E c.m. = 8.5 MeV to 25 μb at E c.m. = 9.0 MeV for the heavy-ion radiative capture process are discussed in terms of the interplay between statistical and structural aspects of the process.

Microscopic study ofCa40+Ni58,64fusion reactions

“…In particular, the fragments are in contact during ∼ 1 zs (10 −21 s) before fusion is decided. Similar times were obtained for near barrier collisions in lighter [38,71] and similar [14,28] mass regions. These times are relatively short in comparison with heavier systems computed with TDHF where typical contact times of few zeptoseconds [72] or more in case of quasi-fission reactions [43,53,[73][74][75] are often obtained, leading to possible large mass transfer [76,77].…”

Clustering in Stable and Exotic Light Nuclei

“…[126]. The 12 C( 16 O,γ) 28 Si data clearly show [124,125] the direct feeding of the prolate 4 + 3 state at 9.16 MeV and the octupole deformed 3 − at 6.88 MeV. This state is the band head of an octupole band which mainly decays to the 28 Si oblate ground state with a strong E 3 transition.…”

“…around 25 MeV excitation energy in 28 Si. We have studied the 12 C( 16 O,γ) 28 Si radiative capture reaction at five resonant energies around the Coulomb barrier by using the zero degree DRAGON spectrometer installed at Triumf, Vancouver [124,125]. Details about the setup, that has been optimized for the 12 C( 12 C,γ) 24 Mg radiative capture reaction in our of previous DRAGON experiments, can be found in Ref.…”

Molecular Structures and Clustering Effects in Reactions Induced by Light Nuclei

“…[60]. The 12 C( 16 O,γ) 28 Si data clearly show [58,59] the direct feeding of the prolate 4 + 3 state at 9.16 MeV and the octupole deformed 3 − at 6.88 MeV. This state is the band head of an octupole band which mainly decays to the 28 Si oblate ground state with a strong E 3 transition.…”

“…around 25 MeV excitation energy in 28 Si [24]. We have studied the 12 C( 16 O,γ) 28 Si radiative capture reaction at five resonant energies around the Coulomb barrier by using the zero degree DRAGON spectrometer installed at Triumf, Vancouver [58,59]. Details about the setup, that has been optimized for the 12 C( 12 C,γ) 24 Mg radiative capture reaction in our of previous DRAGON experiments, can be found in Ref.…”