GEANT 4 simulation of 99Mo photonuclear production in nanoparticles

GEANT 4 Monte-Carlo simulation toolkit is used to study the kinematic recoil method of 99Mo photonuclear production. Simulation for bremsstrahlung photon spectrum with maximum photon energy 30 MeV showed that for MoO3 nanoparticle escape fraction decreases from 0.24 to 0.08 when nanoparticle size increases from 20 nm to 80 nm. For the natural molybdenum and pure 100Mo we obtained the lower values: from 0.17 to 0.05. The generation of accompanying molybdenum nuclei is significantly lower for pure 100Mo and is about 3.6 nuclei per single 99Mo nucleus, while natural molybdenum nanoparticle produce about 48 accompanying nuclei. Also, we have shown that for high-energy photons escape fraction of 99Mo decreases, while production of unwanted molybdenum isotopes is significantly higher.