Experimental studies and nuclear model calculations on proton-induced reactions on natSe, 76Se and 77Se with particular reference to the production of the medically interesting radionuclides 76Br and 77Br

Abstract

Excitation functions of the reactions natSe(p,x) 75,76,77,82Br, 76Se(p,xn) 75,76Br, 76Se(p,x) 75Se and 77Se(p,xn) 76,77Br were measured from their respective thresholds up to 40 MeV, with particular emphasis on data for the production of the medically important radionuclides 76Br and 77Br. The conventional stacked-foil technique was used. The samples were prepared by a sedimentation process. Irradiations were performed using the compact cyclotron CV 28 and the injector of COSY, both at the Research Centre Jülich. In order to validate the data, nuclear model calculations were performed using the code ALICE-IPPE which is based on the preequilibrium-evaporation model. Good agreement was found between the experimental and theoretical data, except in the high-energy region where the calculated data were somewhat higher. All the measured excitation curves were compared with the data available in the literature. From the experimental data the theoretical yields of all the investigated radionuclides were calculated and plotted as a function of proton energy. The calculated yield of 77Br from the natSe(p,x) 77Br process over the energy range E p=25→15 is 72.7 MBq/μA h and from the 77Se(p,n) 77Br reaction over E p=15→6 MeV it is 86.2 MBq/μA h. The yield of 76Br from the 76Se(p,n) 76Br reaction for E p=15→8 is 360.1 MBq/μA h and from the 77Se(p,2n) 76Br reaction for E p=28→18 MeV it is 879.2 MBq/μA h. The radionuclidic impurity levels are discussed.