EXCITATION OF AG-107M,AG-109M ISOMERIC STATES IN THE INELASTIC-SCATTERING OF FAST-NEUTRONS FROM THE IBR-2 REACTOR OF JINR

The cross sections for the excitation of long-lived isomers of Ag-107, Ag-109 nuclei are measured in the inelastic scattering of fast neutron s from the IBR-2 reactor of JLNR (Dubna). The measurements are perform ed by means of comparison with the yield of the Rh-103m isomer, for wh ich the excitation cross sections are known over a wide energy range f or similar reactions induced by monochromatic neutrons. The measured c ross sections proved to be sigma(Ag-107m) = 204 +/- 18 mb and sigma(Ag -109m) = 262 +/- 26 mb. These values are significantly smaller than th e cross section for the excitation of the Rh-103m isomer. An analysis employing information about the arrangement of energy levels in Rh and Ag and about transitions between these levels, as well as data on the spectra of gamma rays emitted in (n, n'gamma) reactions, reveals that the distinction between the cross sections for the excitation of Rh a nd AE isomers can be explained by the difference in the population of corresponding levels of Rh and Ag nuclei.