Cross section data for the production of the positron emitting niobium isotope 90Nb via the 90Zr(p, n)-reaction

Abstract

Summary The radioisotope 90Nb decays with a positron branching of 53% and a relatively low β+-energy of E mean = 0.66 MeV and E max = 1.5 MeV. Its half-life of 14.6 h makes it especially promising for quantitative investigation of biological processes with slow distribution kinetics using positron emission tomography. To optimise its production, the excitation functions of 90Zr(p, xn)-processes were studied over the proton energy range of 7.5 to 19 MeV via the stacked-foil technique using both natZr and 99.22% enriched 90ZrO2 as targets. Thick target yields of 90Nb were calculated from the measured excitation functions and were verified experimentally. The optimum energy range for the production of 90Nb via the 90Zr(p, n)-process was found to be E p = 17 → 7 MeV, with a yield of 600 MBq 90Nb/µA h. The yield and radionuclidic purity of 90Nb over the energy range of E p = 17.6 → 8.1 MeV were determined experimentally using natZr. At 4 h after EOB the yield of 90Nb was found to be 290 MBq/µA h and its radionuclidic purity ≥ 95%.