Measurement and analysis of the ${}^{246}$Cm and ${}^{248}$Cm neutron capture cross-sections at the EAR2 of the n_TOF facility at CERN

The ${}^{246}$Cm(n,γ) and ${}^{248}$Cm(n,γ) cross-sections have been measured at the Experimental Area 2 (EAR2) of
the n_TOF facility at CERN with three C6 D6 detectors. This measurement is part of a collective effort to improve the cap-
ture cross-section data for Minor Actinides (MAs), which are required to estimate the production and transmutation
rates of these isotopes in light water reactors and innovative reactor systems. In particular, the neutron capture in
${}^{246}$Cm and ${}^{248}$Cm open the path for the formation of other Cm isotopes and heavier elements such as Bk and Cf and
the knowledge of (n,γ) cross-sections of these Cm isotopes plays an important role in the transport, transmutation and
storage of the spent nuclear fuel. The reactions ${}^{246}$Cm(n,γ) and ${}^{248}$Cm(n,γ) have been the two first capture measure-
ments analyzed at n_TOF EAR2. Until this experiment and two recent measurements performed at J-PARC, there was
only one set of data of the capture cross-sections of ${}^{246}$Cm and ${}^{248}$Cm, that was obtained in 1969 in an underground
nuclear explosion experiment. In the measurement at n_TOF a total of 13 resonances of 246 Cm between 4 and 400 eV and
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5 of ${}^{248}$Cm between 7 and 100 eV have been identified and fitted. The radiative kernels obtained for ${}^{246}$Cm are compati-
ble with JENDL-5, but some of them are not with JENDL-4, which has been adopted by JEFF-3.3 and ENDF/B-VIII.0.
The radiative kernels obtained for the first three ${}^{248}$Cm resonances are compatible with JENDL-5, however, the other
two are not compatible with any other evaluation and are 20 and 60% larger than JENDL-5.