Production and characterization of $^{111}Ag$ radioisotope for medical use in a TRIGA Mark II Nuclear Reactor.

RadioPharmaceutical Therapy (RPT) comes forth as a promising technique to treat a wide range of tumors while ensuring low collateral damage to nearby healthy tissues. Recently $^{111}Ag$ was proposed as a promising core of a therapeutic radiopharmaceutical for the treatment of large tumors given its penetrating $\beta$-emission. Moreover, it also emits two $\gamma$-rays ({342 ${keV} I_{\gamma}=6.7%$ and $245 {keV} I_{\gamma}=1.24%$), suitable for SPECT imaging, making the therapy follow-up feasible. Finally, its half-life of $7.5 {days}$ allows for all the mandatory radiochemical procedures that lead from the radioisotopes to the actual radiopharmaceutical. In this contribution, the production of $^{111}Ag$ via neutron activation inside a nuclear reactor was modeled using two different Monte Carlo codes (MCNPX and PHITS) and compared with experimental measurements. The whole process was simulated starting from an MCNPX-based reactor model. Irradiation experiments were carried out using both natural and enriched palladium samples, irradiated inside the central thimble of a Triga Mark II Research Reactor. A natural palladium sample was measured also after the chemical separation procedure.