Angular distribution in the neutron-induced fission of actinides

Leong, L.S.; Tassan-Got, L.; Tarrio, D.; Audouin, L.; Paradela, C.; Duran, I.; Le Naour, C.; Altstadt, S.; Andrzejewsky, J.; Barbagallo, M.; Bécares, V.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Eleftheriadis, C.; Dzysiuk, N.; Fraval, K.; Ferrari, A.; Giubrone, G.; Ganesan, S.; Gonçalves, I.F.; Jericha, E.; Gurusamy, P.; Gunsing, F.; Guerrero, C.; Griesmayer, E.; Korschinek, G.; Kokkoris, M.; Koehler, P.; Kivel, N.; Karadimos, D.; Käppeler, F.; Kadi, E.; Manousos, A.; Losito, R.; Leeb, H.; Lederer, C.; Langer, C.; Krtička, M.; Kroll, J.; Mendoza, E.; Mengon, A.; Meaze, M.; Mastromarco, M.; Martínez, T.; Massimi, C.; Marganiec, J.; Praena, J.; Plompen, A.; Pignatari, M.; Perkowski, J.; Pavlik, A.; Mondelaers, W.; Mirea, M.; Mingrone, T.; Schumann, D....

Abstract

Above 1 MeV of incident neutron energy the fission fragment angular distribution (FFAD) has generally a strong anisotropic behavior due to the combination of the incident orbital momentum and the intrinsic spin of the fissioning nucleus. This effect has to be taken into account for the efficiency estimation of devices used for fission cross section measurements. In addition it bears information on the spin deposition mechanism and on the structure of transitional states. We designed and constructed a detection device, based on Parallel Plate Avalanche Counters (PPAC), for measuring the fission fragment angular distributions of several isotopes, in particular 232 Th. The measurement has been performed at n-TOF at CERN taking advantage of the very broad energy spectrum of the neutron beam. Fission events were recognized by back to back detection in coincidence in two position-sensitive detectors surrounding the targets. The detection efficiency, depending mostly on the stopping of fission fragments in backings and electrodes, has been computed with a Geant4 simulation and validated by the comparison to the measured case of 235 U below 3 keV where the emission is isotropic. In the case of 232 Th, the result is in good agreement with previous data below 10 MeV, with a good reproduction of the structures associated to vibrational states and the opening of second chance fission. In the 14 MeV region our data are much more accurate than previous ones which are broadly scattered. © Owned by the authors, published by EDP Sciences, 2013.

Citation

Leong, L., Tassan-Got, L., Tarrio, D., Audouin, L., Paradela, C., Duran, I., Le Naour, C., Altstadt, S., Andrzejewsky, J., Barbagallo, M., Bécares, V., Bečvář, F., Belloni, F., Berthoumieux, E., Billowes, J., Boccone, V., Bosnar, D., Brugger, M., Calvino, F., Calviani, M., …González, R. (2013). Angular distribution in the neutron-induced fission of actinides. EPJ Web of Conferences, 62, 08003. https://doi.org/10.1051/epjconf/20136208003

• Journal Article Type: Article
• Acceptance Date: Jun 1, 2013
• Online Publication Date: Dec 13, 2013
• Publication Date: Dec 1, 2013
• Deposit Date: Jun 29, 2018
• Publicly Available Date: Jul 24, 2018
• Journal: EPJ Web of Conferences
• Print ISSN: 2100-014X
• Publisher: EDP Sciences
• Peer Reviewed: Peer Reviewed
• Volume: 62
• Article Number: 08003
• Pages: 08003
• ISBN: 9782759811236
• DOI: https://doi.org/10.1051/epjconf/20136208003
• Public URL: https://hull-repository.worktribe.com/output/561654
• Publisher URL: https://www.epj-conferences.org/articles/epjconf/abs/2013/23/epjconf_fission2013_08003/epjconf_fission2013_08003.html
• Contract Date: Jun 29, 2018