$T_{1/2} =~87.3 \pm 1.1~ms$.

    Since the second method is less subject to errors than the other methods, we recommend the value of $T_{1/2}= 91.1 \pm 0.5~ms$ as the half-life of $^{22}Al$.\

2.  Beta-delayed charged particle decay\

    After implantation of $^{22}$Al in the E4 detector, an energy spectrum of $\beta$-delayed charged particles was obtained as shown in figure \[fig:pro22al\]. The figure shows the spectrum without any condition and, shaded, the spectrum in coincidence with $\beta$ particles detected in the last detector. As discussed in the simulation section (section \[sec:3\]), this condition provides a better energy resolution of the proton peaks. Up to 25 peaks are visible. The energy measured is the total decay energy which was corrected for the pulse-height defect [@ratkowski].

    The branching ratio for a transition is defined as the total area of the proton peak in the unconditioned spectrum divided by the total number of $^{22}Al$ implanted. The areas of the proton peaks were determined using the method described in the simulation section (see section \[sec:3\]).\
    First, we determined the two ratios $R_1$ and $R_2$. The ratio $R_1=32.7\%$ was determined by dividing the total number of counts in the conditioned proton spectrum (E5 &gt;0) by the total number 