Excitation functions of ⁸⁵ Rb( p,n ) 85m,g Sr and ⁸⁷ Rb( p,n ) 87m Sr reactions from threshold to 15 MeV: possibility of production of ⁸⁵ Sr at a low-energy accelerator

Excitation functions of the reactions 85 Rb( p,n ) 85m Sr, 85 Rb( p,n ) 85m,g Sr and 87 Rb( p,n ) 87m Sr were measured using the activation technique in the proton energy range of 2–5 MeV with a low-energy Tandem Accelerator. Our new data sets, combined with those of Kastleiner et al. data obtained previously at FZJ using enriched target 85 Rb, provide complete excitation functions of the 85 Rb( p,n ) 85m Sr and 85 Rb( p,n ) 85m,g Sr reactions. The experimental data were reproduced well by a model calculation using the code TALYS-2.0 after selection of a few input parameters, confirming the reliability of the experimental data. In contrast, model calculations based on global parameters in the data library TENDL-2023 overestimated the cross sections by nearly a factor of two compared to TALYS-2.0. The isomeric cross-section ratio 85m Sr/ 85g Sr was experimentally determined from the measured activities at the end of bombardment (EOB) up to 5 MeV. Above 5 MeV, the isomer ratio was also derived from the cross sections reported by Kastleiner et al., extending the information upto 15 MeV. The trend was interpreted in terms of the reaction energy available and the effect of spin distribution of the level density. Finally, the 85 Rb( p,n ) 85 Sr reaction is demonstrated to be a promising route for the production of radionuclidically pure 85 Sr at a small cyclotron, possibly for medical applications.