High-accuracy determination of the U-238/U-235 fission cross section ratio up to approximate to 1 GeV at n_TOF at CERN

作者：Paradela C^*; Calviani M; Tarrio D; Leal Cidoncha E; Leong L S; Tassan Got L; Le Naour C; Duran I; Colonna N; Audouin L; Mastromarco M; Lo Meo S; Ventura A; Aerts G; Altstadt S; Alvarez H; Alvarez Velarde F; Andriamonje S; Andrzejewski J; Badurek G; Barbagallo M; Baumann P; Becares V; Becvar F; Belloni F; Berthier B; Berthoumieux E; Billowes J; Boccone V; Bosnar D; Brugger M; Calvino F; Cano Ott D; Capote R; Carrapico C

来源：Physical Review C, 2015, 91(2): 024602.

DOI：10.1103/PhysRevC.91.024602

The U-238 to U-235 fission cross section ratio has been determined at n_TOF up to approximate 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 approximate to 1 GeV.

• 出版日期2015-2-9
• 单位中国地震局