Nuclear model calculations on proton and deuteron induced reactions on Te-122 and Te-120 with particular reference to the formation of the isomeric states I-120m,I-g

Nuclear model calculations were performed on (p,xn) reactions on Te-122 and Te-120, and (d,xn) reactions on Te-120. The computer code used (STAPRE) in corporates statistical and precompound models as well as nuclear structure effects. The total cross-sections of (p,xn) and (d,xn) processes leading to the formation of the radioisotopes I-119, I-120g, I-121 and I-122 are desc ribed well by the calculations. The isomeric cross-section, however, is rat her difficult to calculate. The yield of the high spin isomer (I-120m) depe nds on the type of reaction involved and increases with the increasing proj ectile energy. From an analysis of the energy dependence of the isomeric cr oss-section ratio, the excitation energy of I-120m was deduced to be 550 +/ - 50 keV and its spin and parity as 4(+). The experimental data reported ea rlier and the theoretical analysis presented in this work allow to define t he optimum conditions for the production of the medically important beta(+) emitter I-120g With enhanced confidence. (C) 2000 Elsevier Science Ltd. Al l rights reserved.