Systematic TALYS modeling and statistical optimization of alpha-induced production and radionuclidic purity of 66 Ga, 67 Ga, and 68 Ga

Abstract The medically relevant gallium radionuclides 66 Ga, 67 Ga, and 68 Ga are increasingly demanded for PET imaging and radiopharmaceutical development, yet their alpha-induced production routes often suffer from model-to-data discrepancies and practical trade-offs between yield and radionuclidic impurities. In this work, I present a reaction-specific TALYS-2.0 calibration and decision framework for alpha-irradiation of Cu, Zn, and Ga targets, where key nuclear inputs (level-density, alpha-optical model, and pre-equilibrium options) are screened in a full-factorial scheme and ranked against EXFOR measurements using combined statistical and shape-agreement criteria. The selected best-fit models are then used to generate validated excitation functions, estimate thick-target yields, and determine practical optimum energy windows that balance productivity with impurity suppression. To further enhance radionuclidic purity under realistic operation, post-irradiation cooling time is optimized through TALYS/ISOTOPIA activity-decay calculations, enabling time-dependent purification strategies. The analysis indicates that several routes can approach ∼100% purity for 66 Ga and 67 Ga at suitably selected cooling times while maintaining AOCT/AEOB typically above 50%, whereas most 68 Ga routes attain maximum purity at or near end-of-bombardment due to its short half-life. Overall, the study delivers a validated, data-benchmarked set of TALYS model selections and actionable guidance on target choice, energy window, and cooling time to support medium-energy medical cyclotron production of gallium radionuclides.