G. Tabacaru

Experimental determination of the 7Be+p scattering lengths

The Be-7 + p elastic cross section has been measured at the Centre de Recherches du Cyclotron RIB facility at Louvain-la-Neuve in the c.m. energy region from 0.3 to 0.75 MeV by bombarding a proton-rich target with a radioactive 7Be beam. The recoil protons have been detected in the angular range theta(c.m.) = 120.2degrees-131.1degrees and theta(c.m.) = 156.6degrees-170.2degrees using the LEDA system. From a R-matrix analysis of the cross section data. we obtain the energy and the width of the I resonance (E-X = 0.77 MeV). The iota = 0 scattering lengths a(01) = 25 +/- 9 fm (channel spin I = 1) and a(02) = -7 +/- 3 fm (channel spin I = 2) have been deduced. They are compared to values expected from charge-symmetry properties. Implications on the low energy S-factor of the Be-7(p,gamma)B-8 reaction are discussed

β-decay of [sup 23]Al and nova nucleosynthesis

We have studied the β‐decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton intensities of the IAS in 23Mg and to determine the absolute proton branching ratios by combining our results to the latest γ‐decay data. Experimental technique, results and the relevance for nova nucleosynthesis are discussed.

Study of the 10B(p,α)7Bereaction through the indirect Trojan Horse method

Boron abundances in stellar atmospheres, as well as berillium and lithium ones, can give useful hints for non-standard transport processes discrimination in stars. They can also be relevant for understanding several astrophysical processes (e.g. primordial nucleosynthesis and spallation reactions in ISM). A comprehensive study of Li Be B abundances can therefore confirm or not the presence of non-standard mixing processes in stellar envelopes. For this reason nuclear processes producing or depleting boron isotope abundance need to be studied at astrophysical energies. The 10 B ( p ,α) 7 Be reaction has been studied by means of the Trojan Horse Method. The Trojan Horse Method was thus applied to the 10 B ( d ,α 7 Be ) n reaction, studied at 24 MeV. The obtained results will be discussed.

Spectroscopy of the proton drip line nucleus 19Na by 1H(18Ne,p)18Ne elastic scattering

Abstract We have studied the resonant elastic scattering reaction 18 Ne+p in reverse kinematics, by using the intense (4 × 10 6 pps) 18 Ne radioactive beam at the Centre de Recherches du Cyclotron RIB facility at Louvain-la-Neuve. The recoil protons were detected at 20 different angles in the LEDA segmented silicon detector. The resulting elastic scattering cross sections have been analysed using the R-matrix method. We have observed for the first time the second excited state ( J π = 1/2+, l = 0) of the proton-rich nucleus 19 Na at the center-of-mass energy E c.m. = 1.066 ± 0.003 MeV with a proton width Γ p = 101 ± 3 keV. The Coulomb shift between the 1/2+ mirror levels in 190 and 19 Na is 0.73 MeV, among the largest values currently observed in light exotic nuclei.