Theoretical study of Nb isotope productions by muon capture reaction on 100 Mo
Abstract
The isotope 99 Mo , the generator of 99m Tc used for diagnostic imaging, is supplied by extracting from fission fragments of highly enriched uranium in reactors. However, a reactor-free production method of 99 Mo is searched over the world from the point of view of nuclear proliferation. Recently, 99 Mo production through a muon capture reaction was proposed and it was found that about 50 \, \% of 100 Mo turned into 99 Mo through 100 Mo ( μ-, n ) reaction [arXiv:1908.08166]. However, the detailed physical process of the muon capture reaction is not completely understood. We, therefore, study the muon capture reaction of 100 Mo by a theoretical approach. We used the proton-neutron QRPA to calculate the muon capture rate. The muon wave function is calculated with considering the electronic distribution of the atom and the nuclear charge distribution. The particle evaporation process from the daughter nucleus is calculated by a statistical model. From the model calculation, about 38 \, \% of 100 Mo is converted to 99 Mo through the muon capture reaction, which is in a reasonable agreement with the experimental data. It is revealed that negative parity states, especially 1- state, play an important role in 100 Mo ( μ-, n ) 99 Nb . The feasibility of 99 Mo production by the muon capture reaction is also discussed. Isotope production by the muon capture reaction strongly depends on the nuclear structure.