THE SPECTROSCOPY OF AL-22 - A BETA-P, BETA-2P AND BETA-ALPHA EMITTER

In an experiment at the LISE3 facility of GANIL, we produced the proto n-rich isotope Al-22 by the fragmentation of a Ar-36 primary beam at 9 5 MeV/nucleon. After implantation in a detector telescope, the decay o f Al-22 via beta-delayed proton emission, beta-delayed two-proton emis sion as well as, for the first time, via beta-delayed alpha emission h as been studied. An alpha peak has been observed at (3.27 +/- 0.04) Me V with a branching ratio of (0.31 +/- 0.09) %. The comparison of the d ifferent decay channels to those of the mirror nucleus F-22 and to she ll-model calculations favor a 3(+) state as being the ground state of Al-22. A half life of T-1/2 = (59 +/- 3) ms has been measured. (C) 199 7 Elsevier Science B.V.