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(p, xn) Reactions induced in 169Tm, 181Ta and 209Bi with 20 to 45 MeV protons

1971; Elsevier BV; Volume: 166; Issue: 3 Linguagem: Inglês

10.1016/0375-9474(71)90909-2

1873-1554

C. Birattari, E. Gadioli, A. M. Grassi Strini, G. Strini, G. Tagliaferri, L. Zetta,

Nuclear reactor physics and engineering

The excitation functions of the reactions 169Tm, 181Ta and 209Bi (p, xn) for x = 3, 4 have been measured at proton energies from 20 to 45 MeV. The experimental curves are analysed in terms of a sum of statistical and pre-compound contributions, the last one evaluated according to the model proposed by Griffin and Blann. The cross section for pre-compound neutron and proton emission appears to constitute a relevant portion of the total reaction cross section σR in all the energy interval examined. Correspondingly, the fraction of σR accounted for by the compound nucleus formation cross section is found to be as low as some 30 % for 30 ⪅ Ep ⪅ 40 MeV.