[en] In the experiment performed at GANIL (France) we have studied the β-delayed particle emission of the T_z = -3/2 ³³Ar and T_z = -2 ³²Ar proton emitters. Protons are emitted within the wide window (around 10 MeV) of excited states in ³³Cl and ³²Cl feeding the ground and the excited states of ³²S and ³¹S. Proton-γ coincidences have been used to determine the B(GT) strength in this region of excitation energy allowing us to reassign proton transitions to higher excited state with respect previous studies. The main motivation to revisit these nuclei is the increase of granularity and sensitivity of the charged particle detectors and the high sensitivity and large angular coverage obtained by the use of the CLOVER detectors.

[en] The aim of this work is to revisit the decay of Argon ³²Ar with special emphasis in the p-γ coincidences. The study was motivated by the increase in granularity and sensitivity of the charged particle detectors and by the high sensitivity and large angular coverage obtained by the use of CLOVER detectors

[en] A complete kinematics study of the ¹⁰B(³He,pααα) and ¹¹B(³He,dααα) reactions has been performed to study the multi-particle break-up of ¹²C resonances above the triple-alpha threshold. Four-particle coincidence detection gives us complete information on the direction and energy of the individual alpha particles from the decay of ¹²C, allowing us to extract new information on the structure of ¹²C which we shall present in this contribution. We have observed gamma de-excitation of the T = 1 15.11 MeV resonance using charged particle detectors, and have constructed Dalitz plots of the individual resonances in ¹²C using the complete kinematics information of the alpha particles which come from their break-up.

[en] The reaction ³He+¹¹B→d+¹²C* has been used to populate resonances in ¹²C up to an excitation energy of 15 MeV. The subsequent breakup to three α particles has been measured in complete kinematics. Dalitz plots are used to visualize and analyze the data. The Dalitz plot intensity distribution exhibits zero points characteristic of the total spin and parity of the 3α system allowing us to determine the spin and parity of a state in ¹²C at 13.35 MeV whose quantum numbers were hitherto not well established. The Dalitz plot intensity distributions of the 2^- state at 11.83 MeV and the 1⁺ state at 12.71 MeV are compared with the predictions of a recent three-body calculation as well as with simpler models. All are able to reproduce the gross structures seen in the Dalitz plot, but none give an accurate description of the detailed profile of the distributions.

[en] A complete kinematics study of the ¹⁰B(³He,pααα) and the ¹¹B(³He,dααα) reactions has been performed to study the multi-particle break-up of ¹²C resonances above the triple-alpha threshold. The values of energy and widths of some states has been improved, and in states of natural parity partial branches of decay through the ground state of ⁸Be have been extracted. The influence of the 'ghost' of the ⁸Be ground state has been taken into account in order to clarify the partial branches.

[en] The half-lives of ³⁸Ca and ³⁹Ca have been measured at ISOLDE of CERN. The REXTRAP facility was used to prepare ultra-clean samples of radioactive nuclei for precision decay spectroscopy. ³⁸Ca is one of the T_z=-1,0⁺ →0⁺β -emitting nuclides used to determine the vector coupling constant of the weak interaction and the V_ud quark-mixing matrix element. The result obtained, T_1/2=443.8(19) ms, is four times more precise than the average of previous measurements. For ³⁹Ca, a half-life of T_1/2=860.7(10) ms is obtained, a result in agreement with the average value from the literature. (orig.)

[en] A new experimental device, the Silicon Cube detector, consisting of six double-sided silicon strip detectors placed in a compact geometry was developed at CENBG. Having a very good angular coverage and high granularity, it allows simultaneous measurements of energy and angular distributions of charged particles emitted from unbound nuclear states. In addition, large-volume Germanium detectors can be placed close to the collection point of the radioactive species to be studied. The setup is ideally suited for isotope separation on-line (ISOL)-type experiments to study multi-particle emitters and was tested during an experiment at the low-energy beam line of SPIRAL at GANIL.

[en] The proton-rich nucleus ³³Ar has been produced at the low-energy facility SPIRAL at GANIL. Spectroscopic studies of gamma and p emission of this nucleus were performed with the 'Silicon Cube' detection system. The analysis of proton and gamma singles and coincidence spectra allowed us to establish a complete decay scheme of this nucleus. The comparison of the Gamow-Teller strength distribution deduced from our experiment and the theoretical one obtained with the Shell Model permitted the determination of a quenching factor for the Gamow-Teller strength.

[en] The proton-rich nucleus ³³Ar has been studied by detailed proton and γ-ray spectroscopy at the low-energy facility of SPIRAL at GANIL. Proton and γ-ray singles and coincidence measurements allowed to establish a quasicomplete decay scheme of this nucleus. By comparing the proton intensity to different daughter states, tentative spin assignments have been made for some of the states of ³³Cl. The Gamow-Teller strength distribution is deduced and compared to shell-model calculations and a quenching factor is determined. States close to the isobaric analog state are searched for with respect to isospin mixing.

[en] The reactions ¹⁰B(³He,pααα) at 4.9 MeV and ¹¹B(³He,dααα) at 8.5 MeV have been used to investigate the γ decay of states in ¹²C. By measuring the four-body final state in complete kinematics we are able to detect γ transitions indirectly. We find γ transitions from the 15.11 MeV state in ¹²C to the 12.71, 11.83, 10.3 and 7.65 MeV states followed by their breakup into three α particles. The relative γ-ray branching ratios obtained are (1.2±0.3), (0.32±0.12), (1.4±0.2) and (4.4±0.8)%, respectively, with the remaining (92.7±1.0)% of the γ decays going to the bound states. We obtain Γ_α/Γ=(2.8±1.2)% for the isospin-forbidden α decay of the 15.11 MeV state. From the 12.71 MeV state we find γ transitions to the 10.3 and 7.65 MeV states. The relative γ-ray branching ratios are (0.9_-0.5^+0.6) and (2.6_-1.2^+1.6)%, respectively, with the remaining (96.6_-1.3^+1.7)% of the γ decays going to the bound states. Finally, we discuss the relation between the β decay of ¹²N and ¹²B to states in ¹²C and the γ decay of the 15.11 MeV analog in ¹²C to the same states.