Absolute Decay Width Measurements In O-16

The reaction C-12(6)(Li-6(3), d)(8)O-16* at a Li-6 bombarding energy of 42 MeV has been used to populate excited states in O-16. The deuteron ejectiles were measured using the high-resolution Munich Q3D spectrograph. A large-acceptance silicon-strip detector array was used to register the recoil and break-up products. This complete kinematic set-up has enabled absolute alpha-decay widths to be measured with high-resolution in the 13.9 to 15.9 MeV excitation energy regime in O-16; many for the first time. This energy region spans the 14.4 MeV four-alpha break-up threshold. Monte-Carlo simulations of the detector geometry and break-up processes yield detection efficiencies for the two dominant decay modes of 40% and 37% for the alpha+C-12(g.s.) and alpha+C-12(2(1)(+)) break-up channels respectively.