SPECTROSCOPIC STUDIES OF THE BETA-P AND BETA-2P DECAY OF SI-23

Si-23 isotopes have been produced as projectile fragments of a Ar-36 p rimary beam at 95 MeV/nucleon at the LISE3 spectrometer of GANTL. Afte r implantation in a detector telescope, beta-delayed one-proton and be ta-delayed two-proton emission has been observed. The main one-proton peaks are at (1.32+/-0.04)MeV, (2.40+/-0.04)MeV, and (2.83+/-0.06)MeV. The total decay energy for the beta 2p decay is (6.18+/-0.10)MeV for the decay to the ground state and (5.86+/-0.10)MeV for the decay to th e first excited state in the daughter nucleus. However, energetically possible decays via beta pa and beta 3p emission have not been identif ied. The spectra allowed us to determine the excitation energy of the isobaric analogue state in Al-23. This enabled us to calculate the coe fficients of the T = 5/2 isobaric multiplet mass equation for A = 23. The mass excess of the Si-23 ground state was deduced. This value is c ompared to different theoretical predictions. Additionally, we determi ned the branching ratios for the different decay branches. A half-life measurement yielded T-1/2 = (40.7+/-0.4)ms.