On the $\beta$-decay of $^{9}$C

In $\beta$-decay experiments on $^{9}$C at CERN/ISOLDE the $\beta$-strength was determined to the ground state, the 12.2 MeV excited state and the isobaric analog state (IAS) at 14.655 MeV in $^{9}$B. A large $\beta$-strength asymmetry is deduced for the mirror transitions of $^{9}$C and $^{9}$Li to states around 12 MeV excitation energy. A satisfactory description of the three-body decay from a narrow energy region around the 12.2 MeV resonance is obtained within a sequential model involving the ground and first-excited states of $^{5}$Li and $^{8}$Be. From the study of angular correlations the spin of the 12.2 MeV state is determined as 5/2$^{-}$. For the first time the population of the IAS is observed in $\beta$-decay and new information on the decay of this state is obtained. The advantages of a closely packed, highly segmented detector setup are demonstrated. (30 refs).