No abstract

The U-like AT-vacancy production probability in 7.5-MeV/nucleon deep-inelastic 238 U4-238 U collisions has been measured for no-fission, single-fission, and double-fission exit channels. The results are interpreted using quasimolecular orbital correlations for diatomic and triatomic configurations. This leads to the determination of lower limits for the time scale for late fission of U~like products (> 8 and > 4 as) and their probability (> 77% and > 52%), at mean initial-excitation energies of -40 and -105 MeV, respectively. PACS numbers: 25.70.Lm, 21.10.Tg, 25.85.Ge, 34.50.Fa PPAC FIG. details. 1. Schematic of the experimental setup. See text for

Besides characteristic target and projectile x rays, x-ray continua and radiative-electron-capture photons are seen in collisions with relativistic heavy ions ranging in energy from 82 to 422MeV/amu and in atomic number from Xe to U. The angular distribution, centroid energy, cross section, and line shape of the broad radiative-electron-capture lines are analyzed. The observed continua are due to primary-and secondary-electron bremsstrahlung.In the projectile frame, primary bremsstrahlung is the radiative scattering of incident target electrons from the projectile nucleus.The continuum cross sections and angular distributions are calculated, and are compared with experiment. Secondary-electron bremsstrahlung, due to the radiative scattering of ionized target electrons from other target nuclei, is target-thickness dependent, and the cross section increases roughlỹ ith the square of the target atomic number. The calculated primary-electron bremsstrahlung cross sections are lower than experiment.