Published October 1991 | Version v1
Journal article

Fission of complex nuclei induced by 52-MeV monochromatic and polarized photons

  • 1. Istituto Nazionale di Fisica Nucleare, Sezione di Roma 2, Roma (Italy)
  • 2. Dipartimento di Scienze e Tecnologie Chimiche, II Universita di Roma ''Tor Vergata,'' Via E. Carnevale, 00173 Roma (Italy)
  • 3. Dipartimento di Fisica, II Universita di Roma ''Tor Vergata,'' Via E. Carnevale, 00173 Roma (Italy)
  • 4. Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Casella Postale 13, 00044 Frascati (Rm) (Italy)
  • 5. Istituto Nazionale di Fisica Nucleare, Sezione Sanita, Roma (Italy)
  • 6. Laboratorio di Fisica dell'Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Roma (Italy)
  • 7. Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290 Rio de Janeiro (Brazil)

Description

Experimental fissility data from photofission reactions of 232Th, 238U, and 235U nuclei at 52 MeV have been obtained using monochromatic and polarized photon beams and dielectric fission-track detectors. These data, along with literature data for 237Np, 235,238U, 232Th, 209Bi, 208Pb, and 174Yb nuclei have been analyzed within the framework of a simple two-step model for photofission reactions, i.e., absorption of the incident photon by a neutron-proton pair followed by an evaporation-fission competition mechanism for the excited nucleus. For nuclei in the Ta-Np region the trend of calculated fissilities clearly shows shell effects in the vicinity of 208Pb. In the case of 238U the effect of photon polarization on fission direction has also been studied, and isotropy was observed in the fragment azimuthal distribution

Additional details

Publishing Information

Journal Title
Physical Review, C
Journal Volume
44
Journal Issue
4
Series
Phys. Rev., C.
Journal Page Range
1683-1686
ISSN
0556-2813
CODEN
PRVCA