EXCITATION-FUNCTIONS OF HE-3-PARTICLE INDUCED NUCLEAR-REACTIONS ON NATURAL CHROMIUM - POSSIBILITIES OF PRODUCTION OF FE-52,FE-53 AND MN-52 FOR MEDICAL USE

Excitation functions were measured by the stacked-foil technique for ( nat)Cr(He-3, xn) Fe-52,53 and (nat)Cr (He-3, pxn) 52m,52g,54Mn reactio ns from threshold to 36 MeV. Thin foils of a Cr/Ni-alloy (20% Cr, 73% Ni) were used as targets. Additionally, thin samples were prepared by electrolytic deposition of Cr on Au-backing. Thick target yields of Fe -52,53 and Mn-52 were calculated from the measured excitation function s. The optimum He-3-energy ranges for the production of Fe-52, Fe-53 a nd Mn-52 were found to be E(He-3) = 36 --> 17 MeV, E(He-3) = 17 --> 7 MeV and E(He-3) = 36 --> 15 MeV, respectively, with the expected thick target yields of 1.3 MBq (35 muCi)/muAh for Fe-52, 78 MBq (2.1 mCi)/m uAh for Fe-53 and 5.6 MBq (150 muCi)/muAh for Mn-52. For a small scale production of Fe-52,53 and Mn-52 1 mm thick chromium foils were irrad iated at beam currents between 1 and 12 muA. The radioiron was separat ed by anion-exchange chromatography and the radiomanganese via adsorpt ion on Fe(OH)3 followed by purification with anion-exchange chromatogr aphy. In 1 h irradiations the experimental yields at 1 muA amounted to about 70% of the calculated values and at 12 muA to about 45%. For ro utine production at a nominal beam current of 5 muA experimental yield s of about 3.7 MBq (0.1 mCi)/h Fe-52, 220 MBq (5.8 mCi)/30 min Fe-53 a nd 14.8 MBq (0.4 mCi)/h Mn-52 can be expected.