Theoretical study of Nb isotope productions by muon capture reaction on Mo

Moのミュオン捕獲によるNb同位体生成の理論的研究

Ciccarelli, M.*; 湊 太志   ; 内藤 智也*

Ciccarelli, M.*; Minato, Futoshi; Naito, Tomoya*

The isotope Mo, the generator of 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 Mo is searched over the world from the point of view of nuclear proliferation. Recently, Mo production through a muon capture reaction was proposed and it was found that about 50% of Mo turned into Mo through Mo reaction. However, the detailed physical process of the muon capture reaction is not completely understood. We, therefore, study the muon capture reaction of Mo by a theoretical approach. We used the 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 the Hauser-Feshbach statistical model. From the model calculation, about 38% of Mo is converted to Mo through the muon capture reaction, which is in a reasonable agreement with the experimental data. It is revealed that negative parity states, especially state, play an important role in Mo Nb. Isotope production by the muon capture reaction strongly depends on the nuclear structure. To understand the mechanism, excitation energy functions have to be known microscopically.