Breakup branches of Borromean beryllium-9

The breakup reaction ⁹Be(⁴He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in ⁹Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in ⁹Be have been explored including the ⁸Be_g.s. + n, ⁸Be_2⁺ + n and ⁵He_g.s. + ⁴He channels. By imposing the condition that the breakup proceeded via the ⁸Be ground state, clean excitation spectra for ⁹Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose.