Ni-64 MACS case

The Ni-64 MACS suffers for severe discrepancies, amongst the databases available in literature.

The MACS up to kT=100 keV is completely determined by the resolved resonance region, extending in n+⁶⁴Ni up to E_n ~ 500 keV.

kT = 8 keV

kT = 30 keV

In the specific case of kT = 8 keV and kT = 30 keV, the relevant resonances are the first six resonances in Ni-64. Their parameters are reported in the Atlas of Neutron Resonances[1]. For unknown reasons, the nuclear data evaluations of ENDF/B-8.0 or JENDl-4.0 reports considerably higher values of the capture strengths of the first six resonances. That is the origin of the discrepancies between the nuclear data libraries and the KADONIS evaluation, which is based on activation measurements.

A new TOF measurement is, therefore called for.

The capture cross section data files for the ENDF/B-8.0 (ni64ng.b80) and the same with the first 6 resonances replaced by the Mughabghab parameters (ni64ng.mug) are available in the respective links for calculations of the expected yields in EAR2.

References

[1] Atlas of Neutron Resonances
Resonance Properties and Thermal Cross Sections Z = 1–60
Sixth Edition, Volume 1
S.F. Mughabghab
National Nuclear Data Center Brookhaven National Laboratory Upton, NY 11973-5000

-- AlbertoMengoni - 2021-07-12