Constraints on the dipole photon strength for the odd uranium isotopes

Moreno-Soto, J.; Valenta, S.; Berthoumieux, E.; Chebboubi, A.; Diakaki, M.; Dridi, W.; Dupont, E.; Gunsing, F.; Krticka, M.; Litaize, O.; Serot, O.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Babiano-Suarez, V.; Bacak, M.; Barbagallo, M.; Benedikt, T.; Bennett, S.; Billowes, J.; Bosnar, D.; Brown, A.; Busso, M.; Caamaño, M.; Caballero-Ontanaya, L.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Casanovas, A.; Cerutti, F.; Chiaveri, E.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Davies, P. J.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Ducasse, Q.; Durán, I.; Eleme, Z.; Fernández-Domínguez, B.; Ferrari, A.; Finocchiaro, P.; Furman, V.; Göbel, K.; Gawlik-Ramiga, A.; Gilardoni, S.; Gonçalves, I. F.; González-Romero, E.; Guerrero, C.; Heinitz, S.; Heyse, J.; Jenkins, D. G.; Junghans, A.; Käppeler, F.; Kadi, Y.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Kurtulgil, D.; Ladarescu, I.; Lampoudis, C.; Lederer-Woods, C.; Lonsdale, S. J.; Macina, D.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mingrone, F.; Musumarra, A.; Negret, A.; Nolte, R.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Piersanti, L.; Petrone, C.; Pirovano, E.; Porras, I.; Praena, J.; Quesada, J. M.; et al.

doi:10.1103/PhysRevC.105.024618

Constraints on the dipole photon strength for the odd uranium isotopes

Moreno-Soto, J.; Valenta, S.; Berthoumieux, E.; Chebboubi, A.; Diakaki, M.; Dridi, W.; Dupont, E.; Gunsing, F.; Krticka, M.; Litaize, O.; Serot, O.; Aberle, O.; Alcayne, V.; Amaducci, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Babiano-Suarez, V.; Bacak, M.; Barbagallo, M.; Benedikt, T.; Bennett, S.; Billowes, J.; Bosnar, D.; Brown, A.; Busso, M.; Caamaño, M.; Caballero-Ontanaya, L.; Calviño, F.; Calviani, M.; Cano-Ott, D.; Casanovas, A.; Cerutti, F.; Chiaveri, E.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Cosentino, L.; Cristallo, S.; Damone, L. A.; Davies, P. J.; Dietz, M.; Domingo-Pardo, C.; Dressler, R.; Ducasse, Q.; Durán, I.; Eleme, Z.; Fernández-Domínguez, B.; Ferrari, A.; Finocchiaro, P.; Furman, V.; Göbel, K.; Gawlik-Ramiga, A.; Gilardoni, S.; Gonçalves, I. F.; González-Romero, E.; Guerrero, C.; Heinitz, S.; Heyse, J.; Jenkins, D. G.; Junghans, A.; Käppeler, F.; Kadi, Y.; Kimura, A.; Knapová, I.; Kokkoris, M.; Kopatch, Y.; Kurtulgil, D.; Ladarescu, I.; Lampoudis, C.; Lederer-Woods, C.; Lonsdale, S. J.; Macina, D.; Manna, A.; Martínez, T.; Masi, A.; Massimi, C.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Mengoni, A.; Michalopoulou, V.; Milazzo, P. M.; Mingrone, F.; Musumarra, A.; Negret, A.; Nolte, R.; Ogállar, F.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Piersanti, L.; Petrone, C.; Pirovano, E.; Porras, I.; Praena, J.; Quesada, J. M.; Ramos-Doval, D.; Rauscher, T.; Reifarth, R.; Rochman, D.; Sabaté-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Sekhar, A.; Smith, A. G.; Sosnin, N. V.; Sprung, P.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tassan-Got, L.; Torres-Sánchez, P.; Tsinganis, A.; Ulrich, J.; Urlass, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vescovi, D.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Woods, P. J.; Wright, T.; Žugec, P.

Background: The photon strength functions (PSFs) and nuclear level density (NLD) are key ingredients for
calculation of the photon interaction with nuclei, in particular the reaction cross sections. These cross sections are
important especially in nuclear astrophysics and in the development of advanced nuclear technologies.
Purpose: The role of the scissors mode in the M1 PSF of (well-deformed) actinides was investigated by several
experimental techniques. The analyses of different experiments result in significant differences, especially on the
strength of the mode. The shape of the low-energy tail of the giant electric dipole resonance is uncertain as well.
In particular, some works proposed a presence of the E1 pygmy resonance just above 7 MeV. Because of these
inconsistencies additional information on PSFs in this region is of great interest.
Methods: The γ -ray spectra from neutron-capture reactions on the 234U, 236U, and 238U nuclei have been
measured with the total absorption calorimeter of the n_TOF facility at CERN. The background-corrected
sum-energy and multi-step-cascade spectra were extracted for several isolated s-wave resonances up to about
140 eV.
Results: The experimental spectra were compared to statistical model predictions coming from a large selection
of models of photon strength functions and nuclear level density. No combination of PSF and NLD models from
literature is able to globally describe our spectra. After extensive search we were able to find model combinations
with modified generalized Lorentzian (MGLO) E1 PSF, which match the experimental spectra as well as the total
radiative widths.
Conclusions: The constant temperature energy dependence is favored for a NLD. The tail of giant electric dipole
resonance is well described by the MGLO model of the E1 PSF with no hint of pygmy resonance. The M1 PSF
must contain a very strong, relatively wide, and likely double-resonance scissors mode. The mode is responsible
for about a half of the total radiative width of neutron resonances and significantly affects the radiative cross
section.

Physical Review C 105(2022), 024618
DOI: 10.1103/PhysRevC.105.024618
Cited 1 times in Scopus

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