M. Stanoiu

Two-proton radioactivity studies with 45Fe and 48Ni

In an experiment at the SISSI/LISE3 facility of GANIL, we have studied the decay of the two proton-rich nuclei 45Fe and 48Ni. We identified 30 implantations of 45Fe and observed for the second time four implantation events of 48Ni. In 17 cases, 45Fe decays by two-proton emission with a decay energy of 1.154(16) MeV and a half-life of T_1/2 = 1.6+0.5_-0.3 ms. The observation of 48Ni and of its decay allows us to deduce a half-life of T_1/2 = 2.1+2.1_-0.7 ms. One out of four decay events is completely compatible with two-proton radioactivity and may therefore indicate that 48Ni has a two-proton radioactivity branch. We discuss all information now available on two-proton radioactivity for 45Fe and 48Ni and compare it to theoretical models.

Unveiling the intruder deformed 0

The 02(+) state in 34Si has been populated at the GANIL-LISE3 facility through the β decay of a newly discovered 1(+) isomer in 34Al of 26(1) ms half-life. The simultaneous detection of e(+)e(-) pairs allowed the determination of the excitation energy E(02(+))=2719(3)  keV and the half-life T(1/2)=19.4(7) ns, from which an electric monopole strength of ρ(2)(E0)=13.0(0.9)×10(-3) was deduced. The 2(1)(+) state is observed to decay both to the 0(1)(+) ground state and to the newly observed 0(2)(+) state [via a 607(2) keV transition] with a ratio R(2(1)(+)→0(1)(+)/2(1)(+)→0(2)(+))=1380(717). Gathering all information, a weak mixing with the 0(1)(+) and a large deformation parameter of β=0.29(4) are found for the 0(2)(+) state, in good agreement with shell model calculations using a new SDPF-U-MIX interaction allowing np-nh excitations across the N=20 shell gap.

^+_2

Abstract.The

state in

\beta

^{34}

-decay properties of the neutron-deficient nuclei 25Si and 26P have been investigated at the GANIL/LISE3 facility by means of charged-particle and

Si

\gamma

Beta-decay properties of 25 Si and 26 P

-ray spectroscopy. The decay schemes obtained and the Gamow-Teller strength distributions are compared to shell-model calculations based on the USD interaction. B(GT) values derived from the absolute measurement of the

Unveiling the Intruder Deformed02+State inSi34

\beta

Beta decay studies of neutron-rich 21Sc27Co nuclei at GANIL

-decay branching ratios give rise to a quenching factor of the Gamow-Teller strength of 0.6. A precise half-life of

Prolate-Spherical Shape Coexistence at N=28 in 44 S

43.7\: (6)