Angular distribution in the neutron-induced fission of actinides

Autor(en)

L. S. Leong, L. Tassan-Got, D. Tarrio, L. Audouin, C. Paradela, I. Duran, C. Le Naour, S. Altstadt, J. Andrzejewsky, M. Barbagallo, V. Becares, F. Becvar, F. Belloni, E. Berthoumieux, J. Billowes, V. Boccone, D. Bosnar, M. Brugger, F. Calvino, M. Calviani, D. Cano-Ott, C. Carrapico, F. Cerutti, E. Chiaveri, M. Chin, N. Colonna, G. Cortes, M. A. Cortes-Giraldo, M. Diakaki, C. Domingo-Pardo, R. Dressler, N. Dzysiuk, C. Eleftheriadis, A. Ferrari, K. Fraval, S. Ganesan, A. R. Garcia, G. Giubrone, M. B. Gomez-Hornillos, I. F. Goncalves, Enrique M. Gonzalez-Romero, E. Griesmayer, C. Guerrero, F. Gunsing, P. Gurusamy, D. G. Jenkins, E. Jericha, E. Kadi, F. Kaeppeler, D. Karadimos, N. Kivel, P. Koehler, M. Kokkoris, G. Korschinek, J. Kroll, M. Krticka, C. Langer, C. Lederer, H. Leeb, R. Losito, A. Manousos, J. Marganiec, C. Massimi, T. Martinez, P. F. Mastinu, M. Mastromarco, M. Meaze, A. Mengon, E. Mendoza, P. M. Milazzo, T. Mingrone, M. Mirea, W. Mondelaers, Andreas Pavlik, J. Perkowski, M. Pignatari, A. Plompen, J. Praena, J. M. Quesada, T. Rauscher, R. Reifhart, A. Riego, F. Roman, C. Rubbia, R. Sarmento, P. Schillebeeckx, S. Schmidt, D. Schumann, J. L. Tain, G. Tagliente, A. Tsinganis, S. Valenta, G. Vannini, V. Variale, P. Vaz, A. Ventura, R. Versaci, M. J. Vermeulen, V. Vlachoudis, V. Vlastou, A. Wallner, T. Ware, M. Weigand, C. Weiss, T. Wright, P. Zugec

Abstrakt

Above 1MeV 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 Th-232. 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 U-235 below 3 keV where the emission is isotropic. In the case of Th-232, 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.

Organisation(en)

Isotopenphysik

Externe Organisation(en)

Université Paris XI - Paris-Sud, Johann Wolfgang Goethe-Universität Frankfurt am Main

Anzahl der Seiten

7

DOI

https://doi.org/10.1051/epjconf/20136208003

Publikationsdatum

2013

Peer-reviewed

Ja

ÖFOS 2012

103014 Kernphysik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/c824357d-ef3d-407d-a49b-7a51e9f15709