Proton induced reaction / Enriched target / Excitation function / Copper-67 / Gallium-66 and -67 / Chemical separationSummary. The excitation function of the 68 Zn( p, 2 p) 67 Cu reaction was measured radiochemically up to a proton energy of 71 MeV to obtain accurate data for production of the therapy related β − -emitting radioisotope 67 Cu (T 1/2 = 61.9 h). Investigations were also made on the ( p, 2n) and (p, 3n) reactions on 68 Zn. The experimental cross sections of the 68 Zn( p, 2 p) 67 Cu, 68 Zn( p, 2n) 67 Ga and 68 Zn( p, 3n) 66 Ga reactions were compared with published data and with theoretical predictions based on the hybrid-precompound model ALICE-IPPE. Thick target yields of 67 Cu, 67 Ga (T 1/2 = 78.3 h) and 66 Ga (T 1/2 = 9.4 h) were calculated. Production of 67 Cu is feasible only at proton energies above 50 MeV. For the target thickness E p = 70 → 50 MeV, the yield of 67 Cu amounts to 16.9 MBq/µA·h.