Evaluation of cross section data for the low and medium energy cyclotron production of the non-standard positron emitting radionuclide 90Nb

Abstract

The radionuclide 90Nb (T1/2 = 14.6 h) is a promising non-standard β+-emitter, with potential for use in Immuno-PET. Its production was studied using 90Zr, 91Zr, 93Nb and 89Y targets. Experimental excitation functions of the reactions 90Zr(p,n)90Nb, 91Zr(p,2n)90Nb, 90Zr(d,2n)90Nb, 93Nb(p,4n)90Mo(→90Nb) and 89Y(α,3n)90Nb were critically analyzed. The nuclear model codes TALYS 1.9, ALICE-IPPE, and EMPIRE 3.2 were employed to check the consistency and reliability of the experimental data. A well-developed methodology, based on the experimental data and the results of theoretical nuclear models, was used to calculate the recommended data for each excitation function. The same was done for reactions leading to possible radioisotopic impurities. By using the recommended/reference data, thick target yields were calculated for each production route and its corresponding impurity reactions. After a careful analysis and comparison of all production routes, it is concluded that the 90Zr(p,n)90Nb reaction is better for low energy cyclotrons (20 → 5 MeV), and the 91Zr(p,2n)90Nb and 90Zr(d,2n)90Nb reactions are suitable for medium energy cyclotrons (30 → 12 MeV). The routes 93Nb(p,4n)90Mo→90Nb and 89Y(α,3n)90Nb are suitable for high energy cyclotrons (80 → 31 MeV). For each of these production routes, an optimum energy range is suggested. The recommended results for 90Zr(p,n)90Nb and 91Zr(p,2n)90Nb reactions were validated by comparison with the data for the natZr(p,x)90Nb process.