Theoretical modeling of ⁶⁵Zn production via charged particle reactions on ⁶⁶Zn

This study presents a comprehensive theoretical investigation into the production of the medically and industrially relevant radionuclide ⁶⁵Zn via the ⁶⁶Zn (p, pn)⁶⁵Zn, ⁶⁶Zn (d, t)⁶⁵Zn and ⁶⁶Zn (α, αn)⁶⁵Zn reactions. A combination of Monte Carlo transport simulations (Geant4 toolkit and SRIM module) and nuclear reaction modeling (TALYS-2.0) was employed to evaluate the reaction mechanisms, excitation functions, and production yields. Stopping powers and penetration ranges of incident projectiles (proton, deuteron, alpha particle) in ⁶⁶Zn were calculated using Geant4 and SRIM, showing strong mutual agreement. Excitation functions were simulated using both Geant4's hadronic physics models and TALYS-2.0, incorporating various optical model potentials and nuclear level density (NLD) formulations. Theoretical yields of ⁶⁵Zn were determined for each reaction pathway, highlighting a marked improvement in production efficiency with increasing ⁶⁶Zn isotopic enrichment. Geant4 was also utilized to assess the impact of target thickness on cross-section behavior, while final activation values and end-of-bombardment (EOB) activities were estimated for each reaction under standardized irradiation conditions. Among the investigated channels, the ⁶⁶Zn (p, pn)⁶⁵Zn reaction demonstrated the highest production yield and activity, confirming it as the most effective route for ⁶⁵Zn generation within the examined energy range.