Excitation functions of 85Rb(p, xn) 85m,g,83,82,81Sr reactions up to 100 MeV: integral tests of cross section data, comparison of production routes of 83Sr and thick target yield of 82Sr

Abstract

The β + emitter 83Sr ( T 1/2=32.4 h, E β + =1.23 MeV, I β + =24%) is a potentially useful radionuclide for therapy planning prior to the use of the β − emitter 89Sr ( T 1/2=50.5 d). In order to investigate its production possibility, cross section measurements on the 85Rb(p, xn)-reactions, leading to the formation of the isotopes 85m,gSr, 83Sr, 82Sr and 81Sr, were carried out using the stacked-foil technique. In a few cases, the products were separated via high-performance liquid chromatography. For 82Sr, both γ-ray and X-ray spectrometry were applied; in other cases only γ-ray spectrometry was used. From the measured excitation functions, the expected yields were calculated. For the energy range E p=37→30 MeV the 83Sr yield amounts to 160 MBq/μA h and the level of the 85gSr ( T 1/2=64.9 d) and 82Sr ( T 1/2=25.5 d) impurities to <0.25%. In integral tests involving yield measurements radiostrontium was chemically separated and its radioactivity determined. The experimental production data agreed within 10% with those deduced from the excitation functions. The results of the 85Rb(p,3n) 83Sr reaction were compared with the data on the production of 83Sr via the 82Kr( 3He,2n)-process. In the energy range E 3 He =18→10 MeV the theoretical yield of 83Sr amounts to 5 MBq/μA h and the 82Sr impurity to about 0.2%. The method of choice for the production of 83Sr is thus the 85Rb(p,3n)-process, provided a 40 MeV cyclotron is available. During this study some supplementary information on the yield and purity of 82Sr was also obtained.