Efficiency of production (see Eq. 3) of cosmogenic isotopes by primary and secondary protons of energy E in the lunar sample 64 555, as computed here. Panel A: production of ²⁶Al : contributions from different target nuclei are denoted by dashed lines, while the thick red curve is the total sum. Panel B: summary productions of different long-lived cosmogenic isotopes, as denoted in the legend. The red curve is identical to that in panel A.