Activation-measured radiative neutron-capture cross sections for236U,238U, and237Np

Constraining the calculation of U234,236,238(n,γ) cross sections with measurements of the Ullmann1, Kawano2, Baramsai3 et al. 2017Phys. Rev. C

“…The measured cross sections and evaluations are very well represented by the calculations. [39], and Carlson [38] are shown. The tabulated data were obtained from the EXFOR data base [41].…”

A new approach for cross section evaluations in the high energy region

“…The calculated fission cross sections are plotted in Fig. 6 together with the experimental data [31][32][33][34][35][36][37] and other evaluations. Our calculations for the fission cross sections were obtained from the optimized optical model, fission barrier and level density parameters.…”

Measurements of Neutron Capture Cross Section of237Np for Fast Neutrons

“…In Fig. 8, the data of previous measurements are also indicated by open triangles for the data of Stupegia et al, 13) open diamonds for those of Weston and Todd, 9) closed inverse triangles for those of Trofimov and Nemilov,26) open circles for those of Buleeva et al, 15) and closed circles for those of Esch et al 12) The activation method using monochromatic neutrons produced by nuclear reactions was used by Stupegia et al, Trofimov and Nemilov, and Buleeva et al Stupegia et al measured the amount of activated 238 Np by counting decayed -rays of 1026 and 1029 keV using a NaI detector. As was shown in the present measurement, the contamination -rays due to fission products are expected to contribute to this peak area.…”

“…Reflecting such experimental situations, there is an apparent discrepancy among current nuclear data libraries, JENDL-3.3, 16) JENDL/AC-2008, 17) and ENDF/B-VII.0 18) on the neutron capture cross sections of 237 Np in a fast neutron region. Early data for fast neutrons were measured [13][14][15] by irradiating 237 Np samples with monoenergetic neutrons produced by 7 Li(p, n) or 3 H(p, n) reactions, and measuring -rays emitted from the irradiated product 238 Np. These data deviate from one another about 30-40% in the energy region of 100-500 keV.…”

“…1) A more accurate data of the neutron capture cross section of 237 Np has been also strongly requested from the view point of the production of 238 Pu. 2) Although the neutron capture cross section of 237 Np has been extensively studied by using various measurement methods for a wide neutron energy range, [3][4][5][6][7][8][9][10][11][12][13][14][15] the accuracy is quite poor; the uncertainties were evaluated as 15% for the whole energy range in Ref. 1).…”