Étude des isotopes du plomb de masse 200, 198, 196 et 194 formés par réaction (ions lourds, xn)

Abstract

The low-lying excited states of 194, 196, 198, 200Pb have been studied through the de-excitation γ-rays following the reactions Os( 12C, 4n), W( 16O, 4n) and Re( 14N, 5n). Prompt and delayed spectra, γ-γ coincidences, γ-ray angular distributions and γ-ray time distributions have been obtained. Half-lives were measured for the 12 + level in the four isotopes, for the 9 − level in 194, 196, 200Pb, for the 7− level in 200Pb and for the 5− level in 196, 198Pb. The results of microscopic calculations, performed with either a Gaussian interaction or a surface delta interaction, are compared to the experimental level schemes and transition probabilities, and discussed.