Excitation functions of 125Te(p, xn)-reactions from their respective thresholds up to 100 MeV with special reference to the production of 124I

Excitation functions of the nuclear reactions Te-125(p, xn) I-119,I-120m.120g,I-121.122.123.124.125 were measured for the first time From their respective thresholds up to 100 MeV using the stacked-foil technique. Thin samples were prepared by electrolytic deposition of 98.3% enriched Te-125 on Ti-backing. In addition to experimental studies, excitation functions were calculated by the modified hybrid model code ALICE-IPPE. The experimental and theoretical data generally showed good agreement. From the measured cross section data, integral yields of I-123,I-124,I-125 were calculated. The energy range E-p = 21 --> 15 MeV appears to be very suitable for the production of the medically interesting radionuclide I-124 (T-1/2 = 4.18 d; I-beta(+) = 25%). The thick target yield of I-124 amounts to 81 MBq/muA h and the level of I-125-impurity to 0.9%. The Te-125(p,2n)I-124 reaction gives I-124 yield about four times higher than the commonly used Te-124(p.n)I-124 and Te-124(d, 2n)I-124 reactions. The proposed production energy range is too high for small cyclotrons but large quantities of I-124 can be produced with medium-sized commercial machines. (C) 2001 Elsevier Science Ltd. All rights reserved.