Excitation functions of α-particle induced nuclear reactions on highly enriched 92Mo: compartive evaluation of production routes for 94mTc

Excitation functions were measured for 92Mo(α,xn)95,94Ru, 92Mo(α,p)95gTc and 92Mo(α,pn)94m,gTc reactions by the stacked-foil technique using 97% enriched 92Mo as target material. The data for the 92Mo(α,p)95gTc and 92Mo(α,pn)94mTc reactions were determined after a thermochromatographic separation of the reaction products. Thick target yields were calculated from the measured excitation functions. The levels of isotopic impurities were determined experimentally. The optimum α-particle energy range for the production of 94mTc via the 92Mo(α,pn)94mTc and 92Mo(α,2n)94Ru → 94mTc routes at the Compact Cyclotron CV28 was found to be Eα = 26 → 18 MeV. The thick target yield of the 92Mo(α,pn)94mTc reaction in this range was 63 MBq (1.7 mCi)/μAh. The yield of 94mTc via the 94Ru → 94mTc decay during one hour irradiation amounted to 35 MBq (0.95 mCi)/μAh. A critical evaluation of the various production routes for 94mTc is given. The 94Mo(p,n)-process appears to be the method of choice both in terms of 94mTc yield and its radionuclidic purity. (orig.)