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C. Paradela, M. Calviani, D. Tarrio, G. Badurek, E. Griesmayer, E. Jericha, H. Leeb, M. Pigni, -. n_TOF Collaboration et al.:
"High-accuracy determination of the ²³⁸U/²³⁵U fission cross section ratio up to ≈1 GeV at n_TOF at CERN";
Physical Review C, 91 (2015), 024602; 1 - 11.

The ²³⁸U to ²³⁵U fission cross section ratio has been determined at n_TOF up to ≈1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3-4%. The data collected at n_TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ≈1 GeV.

Neutron-induced fission; Neutron physics; A >= 220

http://dx.doi.org/10.1103/PhysRevC.91.024602