Measurement of low-lying states in 9B.

Abstract

A measurement of low-lying states in $^{9}\mathrm{B}$ was conducted using the $^{6}\mathrm{Li}$${(}^{6}$Li,t${)}^{9}$B reaction at a beam energy of 56 MeV. The particles resulting from the decay of $^{9}\mathrm{B}$ into $^{8}\mathrm{Be}$ + p were detected with position sensitive detectors, and relative energy spectra were obtained from the data using the technique of resonant particle decay spectroscopy. This technique provided a very low background, and the ability to separate the $^{9}\mathrm{B}$ states that decay by $^{8}\mathrm{Be}$ + p from those that decay by $^{5}\mathrm{Li}$ + \ensuremath{\alpha}. Results show that a significant portion of the measured spectrum below \ensuremath{\approxeq} 1.5 MeV cannot be explained by the known states which suggests that these counts arise from the mirror of the 1.68 MeV 1/${2}^{+}$ state of $^{9}\mathrm{Be}$. It was also shown that the recently observed 1/${2}^{\mathrm{\ensuremath{-}}}$ state decays via the p${+}^{8}$Be channel.