Search

The kinematically complete measurements of the 7Li(9Be,ααt)5He reaction at Ebeam = 55 and 70 MeV have been performed and the reconstructed 11B excitation energy spectra were compared with the 7Li(9Be,α7Li)5He results obtained at the same beam energies. Evidence was found for the t+8Be(g.s.) decay of the 11B excited states at 13.1 and 14.4 MeV, the α+7Li*(4.652 MeV) decay of the states at 14.4 and 17.5 MeV and for the t+8Be*(3.03 MeV) decay of the 17.5 MeV state in 11B. A study of the relative yields for the decay of the 14.4 MeV state indicates that significant part of α-decay strength goes into the 2α+t three-body decay channel. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The heavy-ion radiative capture reaction, 12C(12C,γ), has been investigated at beam energies around 16 MeV. Three different experiments were performed. Capture cross-sections were obtained by measuring fused 24Mg residues using the FMA at ANL. These were found to significantly exceed values reported earlier. Subsequently, the decay pathways associated with radiative capture were studied in two separate measurements: one with the high-resolution Gammasphere array and a second with a high efficiency BGO array, where gamma rays were recorded in coincidence with 24Mg residues detected at the focal plane of the DRAGON recoil separator at TRIUMF. Both measurements indicate that a substantial fraction of the decay is mediated through high-lying doorway states, possibly associated with the long-predicted shape-isomeric band in 24Mg. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The heavy ion radiative capture reaction 12C(12C,γ) has been investigated around a beam energy of 16 MeV. The total cross-section has been measured with the Fragment Mass Analyser at Argonne National Laboratory and found to be somewhat larger than has previously been measured. A subsequent measurement with the Gammasphere array has shown that a considerable proportion of this extra cross-section relates to a highly non-statistical decay through high-lying states in 24Mg. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The radiative capture reaction involving heavy ions is a relatively unexplored reaction mechanism which affords the possibility of gaining insights into molecular structure in nuclei and exotic, highly-deformed nuclear shapes. The [sup 12] C([sup 12]C,γ) reaction has been studied using an unconventional application of gamma-ray spectroscopy using the Gammasphere array. A resonance for this reaction has been located for E[sub beam]=15.8 MeV. Favored population of the K=2 rotational band in [sup 24]Mg as well as particular states around 10 MeV in excitation is observed. Using a Monte Carlo simulation of the previously uncharacterised high energy efficiency of Gammasphere, we set a lower limit on the cross-section for the species of decays observed of lµb. [ABSTRACT FROM AUTHOR]

Using the very precise value of the baryonic density of the Universe recently obtained by WMAP, Big Bang Nucleosynthesis calculations predict a primordial 7Li abundance which is a factor 2 – 3 higher than that observed in galactic halo dwarf stars. Up to now, the role of the 7Be(d,p)2α reaction has been neglected. We have studied this reaction, for the first time at energies appropriate to the Big Bang environment, at the CYCLONE facility at Louvain-la-Neuve using a radioactive 7Be beam. The experimental set-up is briefly described. Results and consequences for primordial nucleosythensis are discussed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]