Production of 99Mo/99mTc via photoneutron reaction using natural molybdenum and enriched 100Mo: part 1, theoretical analysis

A theoretical analysis was performed for the production of 99Mo via the 100Mo(γ,n)99Mo reaction using natural (natMo) and enriched (100Mo) molybdenum targets in a modified NIRTA® Targetry system. High energy electrons from a linear accelerator were simulated on a tungsten converter to produce bremsstrahlung incident on molybdenum targets using the TALYS computer code. All open channels and decay schemes were used to assess the production rates and final amounts of radioactive and stable components at end-of-bombardment (3-day irradiation), and after 2 h of cooling. Computations were performed at an accelerator energy of 40 MeV, correlating to a maximized photon fluence at 14 MeV. Impurities of Zr and Nb were found when utilizing enriched 100Mo (excluding Mo isotopes). Targets utilizing natMo added substantial stable and radioactive impurities of Mo, Nb, Zr, Y, and Sr; however, all but the Mo impurities can be readily separated. This study confirms the potential of producing 99Mo via 100Mo(γ,n)99Mo using natMo with manageable impurities.