Fast-neutron induced pre-equilibrium reactions on 55Mn and 63,65Cu at energies up to 40 MeV

Excitation functions were measured for the $^{55}$Mn(n,2n)$^{54}$Mn, $^{55}$Mn(n,$\alpha$)$^{52}$V, $^{63}$Cu(n,$\alpha$)$^{60}$Co, $^{65}$Cu(n,2n)$^{64}$Cu, and $^{65}$Cu(n,p)$^{65}$Ni reactions from 13.47 to 14.83 MeV. The experimental cross sections are compared with the results of calculations including all activation channels for the stable isotopes of Mn and Cu, for neutron incident energies up to 50 MeV. Within the energy range up to 20 MeV the model calculations are most sensitive to the parameters related to nuclei in the early stages of the reaction, while the model assumptions are better established by analysis of the data in the energy range 20-40 MeV. While the present analysis has taken advantage of both a new set of accurate measured cross sections around 14 MeV and the larger data basis fortunately available between 20 and 40 MeV for the Mn and Cu isotopes, the need of additional measurements below as well as above 40 MeV is pointed out. Keywords: 55Mn, 63,65Cu, E$\leq$40 MeV, Neutron activation cross section measurements, Nuclear reactions, Model calculations, Manganese, CopperComment: 39 pages, 12 figure

The CIELO collaboration: Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies – 16O, 56Fe, 235,8U and 239Pu – with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality

From flatness to steepness: Updating TALYS covariances with experimental information

This paper presents a practical solution to merge information from experimental measurements and theoretical calculations using Monte Carlo sampling. Parallel to the sampling of theoretical parameters to produce random cross sections, one can also sample from the experimental data and combine both sources of information, leading to the concept of “Symmetric Monte Carlo” (or SMC). The approach is first detailed with a few simple examples and a real case, taking into account more than 600 measurements, is presented for 56Fe.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Neutron activation cross sections on lead isotopes

The cross sections for the reactions Pb-204(n,n(')gamma)Pb-204(m), Pb-204(n,2n)Pb-203, Pb-204(n,2n)Pb-203(m1), Pb-204(n,3n)Pb-202(m), Pb-206(n,3n)Pb-204(m), Pb-206(n,alpha)Hg-203, and Pb-208(n,p)Tl-208 were determined at the IRMM van de Graaff laboratory in the neutron energy range from 14 to 21 MeV. Both natural and enriched samples were irradiated with neutrons produced via the H-3(d,n)He-4 reaction. The induced activities were determined by gamma-ray spectrometry using a HPGe detector in a low-background shield. Neutron fluences were determined with the well-known cross section of the Al-27(n,alpha)Na-24 reaction. Enriched samples were essential to determine the cross sections for the reactions with Pb-204(m) and Pb-206(m) isomers in the final state. Accurate results for reactions with Pb-204,Pb-206 as target nuclei with natural lead samples were enabled through a precise measurement of the isotopic ratios. For a first investigation of the consequences of the present data for nuclear reaction models they were confronted with calculations based on global parameter systematics in a phenomenological and in a microscopic approach and with parameters selected to reproduce the available data. The TALYS code was used for the former two calculations involving parameter systematics while the STAPRE code was used for the latter calculation

New cross section measurements for neutron-induced reactions on Cr, Ni, Cu, Ta and W isotopes obtained with the activation technique

Herein we report on 50Cr(n,x)48V, 58Ni(n,pα)54Mn, 58Ni(n,x)56Co, 63Cu(n,pα)59Fe, 181Ta(n,α)178mLu, 181Ta(n,α)178gLu, 181Ta(n,x)180mHf, 181Ta(n,p)181Hf, 181Ta(n,2n)180gTa, 182W(n,p)182Ta, 183W(n,x)182Ta, 183W(n,p)183Ta, 184W(n,x)183Ta, 184W(n,α)181Hf, 184W(n,p)184Ta, 186W(n,α)183Hf, 186W(n,x)185Ta, 186W(n,p)186Ta, and 186W(n,2n)185mW reaction cross section measurements using the activation technique. The irradiations were carried out at the 7-MV Van de Graaff accelerator at IRMM, Geel. Quasi monoenergetic neutrons with energies between 13.8 and 20.5 MeV were produced via the 3H(d,n)4He reaction at Ed = 1, 2, 3, and 4 MeV. Both natural and samples enriched in 182W, 183W, 184W, and 186W were used to facilitate correction for interference between reactions leading to the same product. Standard γ-ray spectrometry was employed for the measurement of the radioactivity. In addition to the standard detector efficiency calibration a Monte Carlo simulation of the coaxial HPGe detector was performed with the MCNP5 code in order to achieve higher geometry flexibility and better accuracy. The measured results are compared with work by other authors, current evaluated data files, TALYS and EMPIRE calculations using consistent parameter sets

A Systematic Investigation of Reaction Cross Sections and Isomer Ratios for Neutrons up to 20 MeV on Ni-Isotopes and 59Co by Measurements with the Activation Technique and New Model Studies of the Underlying Reaction Mechanisms.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

High resolution neutron (n,xn) cross-section measurements for 206,207,208

Gamma production cross sections for neutron inelastic scattering reactions (n,xn) (x = 1,2,3) were measured for three different highly enriched targets of 206Pb, 207Pb and 208Pb and for 209Bi. Using the known decay schemes of these isotopes, the total inelastic cross sections and level inelastic cross sections were determined. The measurements are continuous in neutron energy and cover a wide interval (from threshold energy up to about 20 MeV). The experiments were performed at the GELINA white neutron source, at the 200 m flight path station with a time resolution of 8 ns, resulting in an unprecedented neutron energy resolution of 1.1 keV at 1 MeV (36 keV at 10 MeV)

High resolution neutron (n,xn) cross-section measurements for 206,207,208Pb and 209Bi from threshold up to 20 MeV

Gamma production cross sections for neutron inelastic scattering reactions (n,xn) (x = 1,2,3) were measured for three different highly enriched targets of 206Pb, 207Pb and 208Pb and for 209Bi. Using the known decay schemes of these isotopes, the total inelastic cross sections and level inelastic cross sections were determined. The measurements are continuous in neutron energy and cover a wide interval (from threshold energy up to about 20 MeV). The experiments were performed at the GELINA white neutron source, at the 200 m flight path station with a time resolution of 8 ns, resulting in an unprecedented neutron energy resolution of 1.1 keV at 1 MeV (36 keV at 10 MeV)