1. Measurement of the $^{235}$U(n, f) cross section relative to the $^{6}$Li(n, t) and $^{10}$B(n, α) standards from thermal to 170 keV neutron energy range at n_TOF
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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., Bečvář, F., Berthoumieux, E., Billowes, J., Bosnar, D., Brown, A., Caamaño, M., Calviño, F., Calviani, M., Cano-Ott, D., Cardella, R., Casanovas, A., Cerutti, F., Chen, Y. H., Chiaveri, E., Cortés, G., Cortés-Giraldo, M. A., Damone, L. A., Diakaki, M., Domingo-Pardo, C., Dressler, R., Dupont, E., Durán, I., Fernández-Domínguez, B., Ferrari, A., Ferreira, P., Furman, V., Göbel, K., García, A. R., Gawlik, A., Gilardoni, S., Glodariu, T., Gonçalves, I. F., González-Romero, E., Griesmayer, E., Guerrero, C., Gunsing, F., Harada, H., Heinitz, S., Heyse, J., Jenkins, D. G., Jericha, E., Käppeler, F., Kadi, Y., Kalamara, A., Kavrigin, P., Kimura, A., Kivel, N., Knapova, I., Kokkoris, M., Krtička, M., Kurtulgil, D., Leal-Cidoncha, E., Lederer, C., Leeb, H., Lerendegui-Marco, J., Lonsdale, S. J., Macina, D., Manna, A., Marganiec, J., Martínez, 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., Sabaté-Gilarte, M., Saxena, A., Schillebeeckx, P., Schumann, D., Sedyshev, P., Smith, A. G., Sosnin, N. V., Stamatopoulos, A., Tagliente, G., Tain, J. L., Tarifeño-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., and Žugec, P.
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13. Climate action ,7. Clean energy - Abstract
The$^{235}$U(n, f ) cross section was measured at n_TOF relative to $^{6}$Li(n, t) and $^{10}$B(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$^{235}$U(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.