Measurement of the 235U(n, f) cross section relative to the 6Li(n, t) and 10B(n, α) standards from thermal to 170 keV neutron energy range at n_TOF

Amaducci, S.; Cosentino, L.; Barbagallo, M.; Colonna, N.; Mengoni, A.; Massimi, C.; Lo Meo, S.; Finocchiaro, P.; Aberle, O.; Andrzejewski, J.; Audouin, L.; Bacak, M.; Balibrea, J.; Becvar, F.; Berthoumieux, E.; Billowes, J.; Bosnar, D.; Brown, A.; Caamano, M.; Calvino, F.; Calviani, M.; Cano-Ott, D.; Cardella, R.; Casanovas, A.; Cerutti, F.; Chen, Y. H.; Chiaveri, E.; Cortes, G.; Cortes-Giraldo, M. A.; Damone, L. A.; Diakaki, M.; Domingo-Pardo, C.; Dressler, R.; Dupont, E.; Duran, I.; Fernandez-Dominguez, B.; Ferrari, A.; Ferreira, P.; Furman, V.; Gobel, K.; Garcia, A. R.; Gawlik, A.; Gilardoni, S.; Glodariu, T.; Goncalves, I. F.; Gonzalez-Romero, E.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Harada, H.; Heinitz, S.; Heyse, J.; Jenkins, D. G.; Jericha, E.; Kappeler, F.; Kadi, Y.; Kalamara, A.; Kavrigin, P.; Kimura, A.; Kivel, N.; Knapova, I.; Kokkoris, M.; Krticka, M.; Kurtulgil, D.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Lerendegui-Marco, J.; Lonsdale, S. J.; Macina, D.; Manna, A.; Marganiec, J.; Martinez, T.; Masi, A.; Mastinu, P.; Mastromarco, M.; Maugeri, E. A.; Mazzone, A.; Mendoza, E.; Milazzo, P. M.; Mingrone, F.; Musumarra, A.; Negret, A.; Nolte, R.; Oprea, A.; Patronis, N.; Pavlik, A.; Perkowski, J.; Porras, I.; Praena, J.; Quesada, J. M.; Radeck, D.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Ryan, J. A.; Sabate-Gilarte, M.; Saxena, A.; Schillebeeckx, P.; Schumann, D.; Sedyshev, P.; Smith, A. G.; Sosnin, N. V.; Stamatopoulos, A.; Tagliente, G.; Tain, J. L.; Tarifeno-Saldivia, A.; Tassan-Got, L.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Warren, S.; Weiss, C.; Woods, P. J.; Wright, T.; Zugec, P.

doi:10.1140/epja/i2019-12802-7

The 235U(n, f) cross section was measured at n_TOF relative to 6Li(n, t) and 10B(n,α) , with high resolution (L= 183. 49 (2) m) and in a wide energy range (25meV-170keV) with 1.5% systematic uncertainty, making use of a stack of six samples and six silicon detectors placed in the neutron beam. This allowed us to make a direct comparison of the yields of the 235U(n, f) and of the two reference reactions under the same experimental conditions, and taking into account the forward/backward emission asymmetry. A hint of an anomaly in the 10-30keV neutron energy range had been previously observed in other experiments, indicating a cross section systematically lower by several percent relative to major evaluations. The present results indicate that the cross section in the 9-18keV neutron energy range is indeed overestimated by almost 5% in the recently released evaluated data files ENDF/B-VIII.0 and JEFF3.3, as a consequence of a 7% overestimate in a single GMA node in the IAEA reference file. Furthermore, these new high-resolution data confirm the existence of resonance-like structures in the keV neutron energy region. The results here reported may lead to a reduction of the uncertainty in the 1-100keV neutron energy region. Finally, from the present data, a value of 249. 7 ± 1. 4 (stat) ± 0. 94 (syst) b·eV has been extracted for the cross section integral between 7.8 and 11eV, confirming the value of 247. 5 ± 3 b·eV recently established as a standard.

Measurement of the 235U(n, f) cross section relative to the 6Li(n, t) and 10B(n, α) standards from thermal to 170 keV neutron energy range at n_TOF / Amaducci S.; Cosentino L.; Barbagallo M.; Colonna N.; Mengoni A.; Massimi C.; Lo Meo S.; Finocchiaro P.; Aberle O.; Andrzejewski J.; Audouin L.; Bacak M.; Balibrea J.; Becvar F.; Berthoumieux E.; Billowes J.; Bosnar D.; Brown A.; Caamano M.; Calvino F.; Calviani M.; Cano-Ott D.; Cardella R.; Casanovas A.; Cerutti F.; Chen Y.H.; Chiaveri E.; Cortes G.; Cortes-Giraldo M.A.; Damone L.A.; Diakaki M.; Domingo-Pardo C.; Dressler R.; Dupont E.; Duran I.; Fernandez-Dominguez B.; Ferrari A.; Ferreira P.; Furman V.; Gobel K.; Garcia A.R.; Gawlik A.; Gilardoni S.; Glodariu T.; Goncalves I.F.; Gonzalez-Romero E.; Griesmayer E.; Guerrero C.; Gunsing F.; Harada H.; Heinitz S.; Heyse J.; Jenkins D.G.; Jericha E.; Kappeler F.; Kadi Y.; Kalamara A.; Kavrigin P.; Kimura A.; Kivel N.; Knapova I.; Kokkoris M.; Krticka M.; Kurtulgil D.; Leal-Cidoncha E.; Lederer C.; Leeb H.; Lerendegui-Marco J.; Lonsdale S.J.; Macina D.; Manna A.; Marganiec J.; Martinez T.; Masi A.; Mastinu P.; Mastromarco M.; Maugeri E.A.; Mazzone A.; Mendoza E.; Milazzo P.M.; Mingrone F.; Musumarra A.; Negret A.; Nolte R.; Oprea A.; Patronis N.; Pavlik A.; Perkowski J.; Porras I.; Praena J.; Quesada J.M.; Radeck D.; Rauscher T.; Reifarth R.; Rubbia C.; Ryan J.A.; Sabate-Gilarte M.; Saxena A.; Schillebeeckx P.; Schumann D.; Sedyshev P.; Smith A.G.; Sosnin N.V.; Stamatopoulos A.; Tagliente G.; Tain J.L.; Tarifeno-Saldivia A.; Tassan-Got L.; Valenta S.; Vannini G.; Variale V.; Vaz P.; Ventura A.; Vlachoudis V.; Vlastou R.; Wallner A.; Warren S.; Weiss C.; Woods P.J.; Wright T.; Zugec P.. - In: THE EUROPEAN PHYSICAL JOURNAL. A, HADRONS AND NUCLEI. - ISSN 1434-6001. - STAMPA. - 55:7(2019), pp. 120.1-120.19. [10.1140/epja/i2019-12802-7]