Deuteron and proton induced nuclear reactions / Enriched 50 Cr and nat Cr targets / Positron emitter 51 Mn / Excitation function / Radiochemical separation / Thick target yieldSummary. The positron emitter 51 Mn (t1/ 2 ϭ 46.2 min, Iβϩ ϭ 97%) is of potential interest in positron emission tomography (PET). With a view to optimizing its production route, excitation functions for deuteron induced nuclear reactions on isotopically enriched (ϳ95%) 50 Cr were determined radiochemically over the energy range of 3 to 13 MeV and for proton induced nuclear reactions on nat Cr in the range of 18 to 38 MeV. Cross sections are presented for the reactions: 50 Cr(d,2n) 50m Mn, 50 Cr(d,n) 51 Mn, 50 Cr(d,t) 49 Cr, 50 Cr(d,p) 51 Cr, 50 Cr(d,A) 48 V, 52 Cr(d,2p) 52 V, nat Cr(p,x) 51 Mn, nat Cr(p,x) 52 Mn, nat