title: Photofission of heavy nuclei at energies up to 4 GeV.
abstract: Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and natPb have been measured simultaneously, using tagged photons in the energy range Egamma=0.17-3.84 GeV. This was the first experiment performed using the Photon Tagging Facility in Hall B at Jefferson Lab. Our results show that the photofission cross section for 238U relative to that for 237Np is about 80% over the entire energy range, implying the presence of important processes which compete with fission. If we assume that for 237Np the photofission probability is equal to unity, we observe a significant shadowing effect, starting below 1.5 GeV.
authors.affiliation: Center for Nuclear Studies, Department of Physics, The George Washington University, Washington, D.C. 20052, USA.
authors.forename: C
authors.initials: C
authors.lastname: Cetina
authors.forename: B L
authors.initials: BL
authors.lastname: Berman
authors.forename: W J
authors.initials: WJ
authors.lastname: Briscoe
authors.forename: P L
authors.initials: PL
authors.lastname: Cole
authors.forename: G
authors.initials: G
authors.lastname: Feldman
authors.forename: P
authors.initials: P
authors.lastname: Heimberg
authors.forename: L Y
authors.initials: LY
authors.lastname: Murphy
authors.forename: S A
authors.initials: SA
authors.lastname: Philips
authors.forename: J C
authors.initials: JC
authors.lastname: Sanabria
authors.forename: H
authors.initials: H
authors.lastname: Crannell
authors.forename: A
authors.initials: A
authors.lastname: Longhi
authors.forename: D I
authors.initials: DI
authors.lastname: Sober
authors.forename: G Y
authors.initials: GY
authors.lastname: Kezerashvili