Re-evaluation of the EURACOS integral shielding experiment series

The EURACOS experiment series (sodium, iron, and no shielding) has been re-evaluated in the scope of the OECD/NEA SINBAD project to determine how useful these benchmarks can be for the validation of the modern nuclear data evaluations. The measured activation rates of different foils as well as unfolded proton recoil spectra at different depths in sodium and iron have been compared to the Monte Carlo calculated parameters. The results suggest good agreement with the experiment only for the high-threshold 32S(n,p) reaction detectors. The comparison of the lower threshold 103Rh(n,n′) and 115In(n,n′) reactions, and the (n,γ) reaction on 197Au under cadmium cover, reveals large discrepancy between the experimental and calculated spatial distributions for these reaction rates which is expected to be due to the uncertainties in the source and background description rather than due to the cross section uncertainties. On the other hand, the unfolded neutron spectra shapes are in relatively good agreement with the calculated ones. The overall results show that the EURACOS Na and Fe experiments cannot be considered of benchmark quality mainly due to unsatisfactory information on the neutron source. Nevertheless, some activation measurements from the EURACOS sodium and iron experiments such as the high threshold reactions and the spectra measurements are potentially useful for modern nuclear data and computer code benchmarking.