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Title: Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons

Abstract

Absolute cross-section measurements for the photofission reactions of {sup 197}Au, {sup nat}Pb, {sup 209}Bi, {sup 232}Th, {sup 238}U, and {sup 235}U nuclei have been performed at an incident photon energy of 69 MeV using monochromatic and polarized photon beams and dielectric fission-track detectors. Nuclear fissility values have been obtained and results are in agreement with those from other laboratories, although in some cases discrepancies are observed between one other. For nuclei in the region of the actinides the fissility result is {approx gt}0.4, while for Au, Pb, and Bi nuclei it only is {similar to}10{sup {minus}3}--10{sup {minus}2}. Results have been interpreted in terms of the primary Levinger's quasideuteron nuclear photoabsorption followed by a mechanism of evaporation-fission competition for the excited nuclei. Shell effects have been taken into account, and they are clearly manifested when fissility is evaluated. The influence of photon polarization on photofission of {sup 238}U also has been investigated, and results have shown isotropy in the fragment azimuthal distribution.

Authors:
; ; ;  [1]; ; ;  [2];  [3];  [4];  [5]
  1. Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPq (BR) Centro Brasileiro de Pesquisas Fisicas-CBPF, Rua Dr. Xavier Sigaud 150, 22290 Rio de Janeiro-RJ, (Brazil)
  2. Dipartimento di Fisica, II Universita' degli Studi di Roma Tor Vergata'', Via E. Carnevale, 00173 Roma, (Italy) Istituto Nazionale di Fisica Nucleare-INFN, Sezione di Roma 2, Roma, (Italy)
  3. Dipartimento di Scienze e Tecnologie Chimiche, II Universita' degli Studi di Rom Torr Vergata'', Via E. Carnevale, 00173 Roma, (Italy) Istituto Nazionale di Fisica Nucleare-INFN, Sezione di Roma 2, Roma, Italy
  4. Istituto Nazionale di Fisica Nucleare-INFN, Laboratori Nazionali di Frascati-LNF, Casella Postale 13, 00044 Frascati, (Italy)
  5. Laboratorio di Fisica dell'Istituto Superiore di Sanita, Viale Regina Elena 299, 00161 Roma, (Italy) Istituto Nazionale di Fisica Nuclea
Publication Date:
OSTI Identifier:
5462995
Resource Type:
Journal Article
Journal Name:
Physical Review, C (Nuclear Physics); (United States)
Additional Journal Information:
Journal Volume: 44:1; Journal ID: ISSN 0556-2813
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BISMUTH 209 TARGET; PHOTOFISSION; GOLD 197 TARGET; LEAD; THORIUM 232 TARGET; URANIUM 235 TARGET; URANIUM 238 TARGET; ANGULAR DISTRIBUTION; CROSS SECTIONS; EXPERIMENTAL DATA; FISSION FRAGMENTS; LEVINGER-BETHE THEORY; MEV RANGE 10-100; MONOCHROMATIC RADIATION; POLARIZED BEAMS; BEAMS; DATA; DISTRIBUTION; ELECTROMAGNETIC RADIATION; ELEMENTS; ENERGY RANGE; FISSION; INFORMATION; METALS; MEV RANGE; NUCLEAR FRAGMENTS; NUCLEAR REACTIONS; NUMERICAL DATA; PHOTONUCLEAR REACTIONS; RADIATIONS; TARGETS; 651920* - Nuclear Properties & Reactions, A=190-219, Experimental; 652020 - Nuclear Properties & Reactions, A=220 & above, Experimental

Citation Formats

Martins, J B, Moreira, E L, Tavares, O A.P., Vieira, J L, Casano, L, D'Angelo, A, Schaerf, C, Terranova, M L, Babusci, D, and Girolami, B. Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons. United States: N. p., 1991. Web. doi:10.1103/PhysRevC.44.354.
Martins, J B, Moreira, E L, Tavares, O A.P., Vieira, J L, Casano, L, D'Angelo, A, Schaerf, C, Terranova, M L, Babusci, D, & Girolami, B. Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons. United States. https://doi.org/10.1103/PhysRevC.44.354
Martins, J B, Moreira, E L, Tavares, O A.P., Vieira, J L, Casano, L, D'Angelo, A, Schaerf, C, Terranova, M L, Babusci, D, and Girolami, B. 1991. "Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons". United States. https://doi.org/10.1103/PhysRevC.44.354.
@article{osti_5462995,
title = {Absolute photofission cross section of sup 197 Au, @Pb, sup 209 Bi, sup 232 Th, sup 238 U, and sup 235 U nuclei by 69-MeV monochromatic and polarized photons},
author = {Martins, J B and Moreira, E L and Tavares, O A.P. and Vieira, J L and Casano, L and D'Angelo, A and Schaerf, C and Terranova, M L and Babusci, D and Girolami, B},
abstractNote = {Absolute cross-section measurements for the photofission reactions of {sup 197}Au, {sup nat}Pb, {sup 209}Bi, {sup 232}Th, {sup 238}U, and {sup 235}U nuclei have been performed at an incident photon energy of 69 MeV using monochromatic and polarized photon beams and dielectric fission-track detectors. Nuclear fissility values have been obtained and results are in agreement with those from other laboratories, although in some cases discrepancies are observed between one other. For nuclei in the region of the actinides the fissility result is {approx gt}0.4, while for Au, Pb, and Bi nuclei it only is {similar to}10{sup {minus}3}--10{sup {minus}2}. Results have been interpreted in terms of the primary Levinger's quasideuteron nuclear photoabsorption followed by a mechanism of evaporation-fission competition for the excited nuclei. Shell effects have been taken into account, and they are clearly manifested when fissility is evaluated. The influence of photon polarization on photofission of {sup 238}U also has been investigated, and results have shown isotropy in the fragment azimuthal distribution.},
doi = {10.1103/PhysRevC.44.354},
url = {https://www.osti.gov/biblio/5462995}, journal = {Physical Review, C (Nuclear Physics); (United States)},
issn = {0556-2813},
number = ,
volume = 44:1,
place = {United States},
year = {1991},
month = {7}
}