β-delayed particle decay of9Cand theA=9, T=1/2nuclear system: Experiment, data, and phenomenological analysis

The $\ensuremath{\beta}$ decay of ${}^{9}\mathrm{C}$ ${(T}_{1/2}=126.5 \mathrm{ms})$ has been studied in two experiments observing about $15\ifmmode\times\else\texttimes\fi{}{10}^{7}$ and $8\ifmmode\times\else\texttimes\fi{}{10}^{7}$ decays, respectively, at the TISOL facility at TRIUMF; different detector configurations were employed in the two experiments. In this first of two papers, the two experimental setups are described, as well as data analysis and a phenomenological approach to deducing branching ratios to and from states in ${}^{9}\mathrm{B}.$ In the experiments single spectra, and double and triple coincidence spectra, were recorded. Several states in ${}^{9}\mathrm{B}$ were observed; $\ensuremath{\beta}$-branching ratios to these states, and particle decay channels from these states, are reported. In particular, secondary decays into the ${}^{5}\mathrm{Li}$ and ${}^{8}\mathrm{Be}$ ground states were observed. With the inclusion of a considerable continuum and additional states, fair agreement with the reported ${}^{9}\mathrm{Li}\mathrm{log}\mathrm{ft}$ values is found with a phenomenological approach for deducing the branching ratios. To extend the discussion, in a second, forthcoming paper, a multichannel, multistate R-matrix analysis of these data will be described.