Molybdenum-99 production via lead and bismuth moderators and milli-structure- ⁹⁸Mo samples by the indirect production technique using the Monte Carlo method

We describe the design of a neutron activator that contains a beryllium target, a lead/bismuth moderator, graphite/PbF₂ reflectors, and a boron absorber. Production of the ⁹⁹Mo isotope using millimeter-sized ⁹⁸Mo samples located in various regions of the activator was simulated using the MCNPX code. If the ⁹⁸Mo samples are placed in the reflector region, the yield increases due to a larger flux of epithermal neutrons. (instruments and methods of investigation)