Spectroscopy of Na: Bridging the two-proton radioactivity of Mg

The unbound nucleus ¹⁸Na, the intermediate nucleus in the two-proton radioactivity of ¹⁹Mg, was studied by the measurement of the resonant elastic scattering reaction H(¹⁷Ne,p)¹⁷Ne performed at 4 A.MeV using a radioactive beam from the SPIRAL Facility. Spectroscopic properties of the low-lying states were obtained in an R-matrix analysis of the excitation function.     

New7Be(p, γ)8B cross section measurement

The⁷Be(p,γ)⁸B cross section has been re-measured using radioactive targets. The zero-energy astrophysical S-factor is found significantly lower than the previously adopted value.     

(68)(28)Ni(40): Magicity versus superfluidity

The neutron-rich (66,68)Ni have been produced at GANIL via interactions of a 65.9A MeV 70Zn beam with a 58Ni target. Their reduced transition probability B(E2;0(+)(1)-->2+) has been measured for the first time by Coulomb excitation in a (208)Pb target at intermediate energy. The B(E2) value for (68)Ni(40) is unexpectedly small. An analysis in terms of large scale shell model calculations stresses the importance of proton core excitations to reproduce the B(E2) values and indicates the erosion of the N = 40 harmonic-oscillator subshell by neutron-pair scattering.     

Faltungsungleichungen auf endlichen abelschen Gruppen

Ohne Zusammenfassung     

Low-energy measurement of the 7Be(p,gamma)8B cross section

We have measured the cross section of the 7Be(p,gamma)8B reaction for E(c.m.) = 185.8, 134.7, and 111.7 keV using a radioactive 7Be target (132 mCi). Single and coincidence spectra of beta+ and alpha particles from 8B and 8Be* decay, respectively, were measured using a large acceptance spectrometer. The zero energy S factor inferred from these data is 18.5+/-2.4 eV b and a weighted mean value of 18.8+/-1.7 eV b (theoretical uncertainty included) is deduced when combining this value with our previous results at higher energies.     

Investigation of the sequential break-up mode6Li→6Li*(31 +)→α+d of 156 MeV6Li projectiles on208Pb in the very forward angular hemisphere

The sequential break-up of 156 MeV⁶Li projectiles colliding with²⁰⁸Pb has been investigated in the very forward angular hemisphere in order to explore the role of the Coulomb and nuclear interaction in inducing projectile break-up processes. The experiments use the Karlsruhe spectrograph Little John with a newly developed technique to detect efficiently break-up pairs of-particles and deuterons emitted with small relative energies and within a small opening angle. The observed differential cross section for the projectile excitation⁶Li⁶Li^* (I=3_i ⁺) has been analysed (together with forward elastic scattering) by a coupled channel approach, and various sensitivities to the nuclear potential and other ingredients have been studied. We conclude, that in the angular region below half the grazing angle the excitation is completely due to the Coulomb force. This feature is a basis for an application of the disintegration approach for studies of radiative capture cross section of astrophysical interest.On leave from Institute of Atomic Physics Bucharest, Romania