Published 2015
NDS Staff Publication
High-accuracy determination of the 238U/ 235U fission cross section ratio up to ≈ 1 GeV at n_TOF at CERN
Creators
- Paradela, C.
- Calviani, M.
- Tarrıo, D.
- Leal-Cidoncha, E.
- Leong, L. S.
- Tassan-Got, L.
- Naour, C. Le
- Duran, I.
- Colonna, N.
- Audouin, L.
- Mastromarco, M.
- Meo, S. Lo
- Ventura, A.
- Aerts, G.
- Altstadt, S.
- Alvarez, H.
- Alvarez-Velarde, F.
- Andriamonje, S.
- Andrzejewski, J.
- Badurek, G.
- Barbagallo, M.
- Baumann, P.
- Be´cares, V.
- Becvar, F.
- Belloni, F.
- Berthier, B.
- Berthoumieux, E.
- Billowes, J.
- Boccone, V.
- Bosnar, D.
- Brugger, M.
- Calvino, F.
- Cano-Ott, D.
-
Capote Noy, R.1
- 1. Nuclear Data Section, IAEA
Description
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.