measured in beam-on/beam-off mode (120 ms of implantation, 300 ms beam-off). The inset in figure \[fig:temps\_vie\] shows the decay-time spectrum in the beam-off period. This spectrum was fitted with an exponential function for the $^{22}Al$ decay and a constant for the background. The decay of the daughter $^{22}Mg$ is the main contributor to this background ($T_{1/2}=3.857~s$). The half-life obtained with this method is $T_{1/2}=~91.9 \pm 1.4~ms$.

    A second analysis was performed by generating, from the same data set, the decay-time spectra in coincidence with the different proton groups. Each point in the figure \[fig:temps\_vie\] represents in y axis the half-life obtained from the fit of a decay-time spectrum in coincidence with a range of proton energies in x axis. The error-weighted mean value for the half-life from this analysis is $T_{1/2}=~91.1 \pm 0.5~ms$. The two points at low energy were not used to avoid the contribution from the contaminants. In fact, the main contaminant $^{22}Mg$ decays only by $\beta-\gamma$ and the $\beta$ particles associated contributes to the proton spectrum at low energies. However, this value is more accurate than the previous one which contains a higher contamination.

    A third analysis with a continuous implantation mode has produced a value of 