Measurement and analysis of theAm241neutron capture cross section at the n_TOF facility at CERN

Abstract

The 241 Am(n,γ ) cross section has been measured at the n_TOF facility at CERN with the n_TOF BaF 2 Total Absorption Calorimeter in the energy range between 0.2 eV and 10 keV. Our results are analyzed as resolved resonances up to 700 eV, allowing a more detailed description of the cross section than in the current evaluations, which contain resolved resonances only up to 150-160 eV. The cross section in the unresolved resonance region is perfectly consistent with the predictions based on the average resonance parameters deduced from the resolved resonances, thus obtaining a consistent description of the cross section in the full neutron energy range under study. Below 20 eV, our results are in reasonable agreement with JEFF-3.2 as well as with the most recent direct measurements of the resonance integral, and differ up to 20-30% with other experimental data. Between 20 eV and 1 keV, the disagreement with other experimental data and evaluations gradually decreases, in general, with the neutron energy. Above 1 keV, we find compatible results with previously existing values.

Measurement of the α ratio and (n,γ) cross section of U235Balibrea1, Cembranos2, Cano‐Ott3 et al. 2020Phys. Rev. CSelf Cite3000View full textAdd to dashboardCite

“…Other analyses performed with the TAC, although without fission tagging detectors, can be found in Refs. [41][42][43][44][45], and the previous test with fission tagging in Ref. [19].…”

“…The TAC efficiency for capture events ε γ was determined by Monte Carlo simulations, similarly to previous works [42,43,45]. The 235 U(n, γ ) cascades were generated with the DICEBOX code [58], adjusting the parameters of the electromagnetic cascades from the LANSCE experimental 235 U(n, γ ) data [7].…”

“…For this analysis we used a pileup correction model very similar to that used in Ref. [45]. This model is based on the same principles as described in Ref.…”

Nuclear data research supported by EURATOM: CHANDA, ERINDA and EUFRAT

“…Measuring the same isotope and reaction in two different facilities to reduce systematic effects. For example 238 U is a reference isotope and 241 Am [5,6] is very difficult to measure because of the high intrinsic radioactivity. Both deserve for different reasons a special effort to reduce the systematic uncertainties.…”

“…Both deserve for different reasons a special effort to reduce the systematic uncertainties. Several sets of measurements using same or similar samples were made for each of these isotopes combining the facilities of GELINA [6] (transmission and capture by C 6 D 6 ) and n_TOF [5] (capture) in this case using 2 different techniques (C 6 D 6 and total absorption calorimeter), the combination of results allows better understanding and qualifying the capture cross section of these isotopes.…”