Excitation functions for the formation of some radioisotopes of rubidium in proton induced nuclear reactions on natKr, 82Kr and 83Kr with special reference to the production of 81Rb(81mKr) generator radionuclide

Excitation functions were measured using the ''stacked gas cell'' technique for the formation of 81Rb, 82mRb, 83Rb and 84Rb in proton induced nuclear reactions on natural krypton and isotopically enriched 82Kr and 83Kr over the proton energy range of 5.30 MeV. From the experimental data for various enrichments of 82Kr, 83Kr, 84Kr and 86Kr in target gases, absolute cross-sections were deduced for the reactions 82Kr(p,2n)81Rb, 83Kr(p,3n)81Rb, 82Kr(p,n)82mRb, 83Kr(p,2n)82mRb, 84Kr(p,3n)82mRb, 83Kr(p,n)83Rb, 84Kr(p,2n)83Rb, 84Kr(p,n)84Rb and 86Kr(p,3n)84Rb. From those data the differential and integral thick target yields of 81Rb were calculated. The method of choice for the production of 81Rb(81mKr) generator radionuclide is the 82Kr(p,2n)-process on highly enriched 82Kr. Our results show that the optimum energy range for production is Ep = 27 → 19 MeV: the thick target yield of 81Rb amounts to 48 mCi (1776 MBq)/μAh and the level of 6.47 h 82mRb impurity to ∼ 7%. Due to the high yield of the process sufficient quantities of 81Rb can be produced even at cyclotrons with Ep ≅ 20 MeV. (author)