Actinium isotope cross sections for 226 Ra(p,xn) reactions measured at low energies.

Cross sections for production of the medical isotope 225 Ac by the 226 Ra(p,2n) reaction have not previously been measured in fine steps over the relevant energy region, and no measurements are presently available in the literature for the actinium contaminant isotopes created by the adjacent 226 Ra(p,n) 226 Ac and 226 Ra(p,3n) 224 Ac reactions. We report thin-target cross-section measurements for production of 224 Ac and 225 Ac by protons of 15.1-16.8 MeV incident on radium. An upper limit for the 226 Ac cross section is also reported.