N. A. Orr

The spectroscopy of 22Al: a βp, β2p and βα emitter

Abstract In an experiment at the LISE3 facility of GANIL, we produced the proton-rich isotope 22Al by the fragmentation of a 36Ar primary beam at 95 MeV/nucleon. After implantation in a detector telescope, the decay of 22Al via β-delayed proton emission, β-delayed two-proton emission as well as, for the first time, via β-delayed α emission has been studied. An α peak has been observed at (3.27 ± 0.04) MeV with a branching ratio of (0.31 ± 0.09) %. The comparison of the different decay channels to those of the mirror nucleus 22F and to shell-model calculations favor a 3+ state as being the ground state of 22Al. A half life of T1/2 = (59 ± 3) ms has been measured.

Beta-p,-2p,-alpha spectroscopy of 22,23,24Si and 22Al

Abstract In an experiment at the LISE3 facility of GANIL, we used the projectile fragmentation of a 36 Ar primary beam at 95 MeV/nucleon to produce neutron-deficient isotopes in the Al-Si region. The selected isotopes were implanted in a detector telescope, where their decay particles were observed. We report here on the study of the βp, β2p, and βα decay of the isotopes 22,23,24 Si and 22 Al. Beta-decay half-lives have been measured. The ground-state mass excess of 23 Si has been determined. Partial decay schemes are presented on the basis of the transitions associated with the observed decay peaks.

Beta-delayed proton spectroscopy of 24Si

Abstract In an experiment at the LISE3 facility of GANIL, we used the projectile fragmentation of a 36 Ar primary beam at 95 MeV/nucleon to produce the isotope 24 Si. The beta decay half-life of 24 Si has been determined to be T 1/2 = (140 ± 8) ms, in agreement with earlier measurements. In addition to the decay of the isobaric analog state, several proton peaks are observed for the first time allowing to identify most of the Gamow-Teller transitions to unbound states and to present a partial decay scheme for 24 Si. These results are compared with shell-model predictions.

Spectroscopy of 22,23,24Si and 22Al

β-delayed one- and two-proton and α spectroscopic studies of the neutron-deficient nuclei 22,23,24Si and 22Al produced in projectile fragmentation of a 36Ar primary beam at 95 MeV/u have been performed at GANIL. Isotopes of interest were analyzed using the LISE3 spectrometer and were implanted in a telescope made of silicon detectors and a micro-strip gaseous counter where decay particles were detected.