E4 or E5. If the $\beta$ particle is followed by proton emission, the energy loss is always sufficient to trigger the acquisition. Otherwise, in the case of $\beta$-$\gamma$ transitions, the energy lost by $\beta$ particles in E3 or E4 is not sufficient to trigger the acquisition. In this case, the acquisition may be triggered by $\beta$ particles detected in the E5 detector. This efficiency must be determined to calculate the branching ratio for the $\beta$-$\gamma$ transitions.

    To study the behaviour of the $\beta$-trigger efficiency, a simulation was performed. It has shown that this efficiency depends strongly on the distance between the detectors E4 and E5 (i.e. on the solid angle). However, for a fixed geometry, the $\beta$-trigger efficiency depends linearly with the $\beta$ energy. For the 4-14 MeV range of interest, the simulation shows that the $\beta$-trigger efficiency varies from 36% to 44%.

Experimental results {#sec:4}
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In the following, we present our experimental results: half-life, $\beta$-delayed $\gamma$ decays, $\beta$-delayed charged-particle emissions as well as coincidences between charged particles and $\gamma$ rays and $\gamma$-$\gamma$ coincidences. These results allow us to determine a detailed experimental decay scheme and to compare it with previous results.\

1.  $^{22}Al$ half-life\
    The $^{22}Al$ half-life was 