Subthreshold Fission Cross Section of²⁴⁰Pu and the Fission Cross Sections of²³⁵U and²³⁹Pu

239Pu neutron resonance parameters revisited and covariance matrix in the neutron energy range from thermal to 2.5 keV

“…Most of the experimental data used in the present evaluation were taken at the Oak Ridge Electron Linear Accelerator (ORELA) between 1971 and 1993 by Gwin et al [11][12][13] for the fission and capture cross sections, by Weston et al [7,9,14] for the fission cross sections and by Harvey et al [15] for the neutron transmissions. These data cover the energy range 0.01 eV to 2.5 keV.…”

“…That is the case of Gwin 1971Gwin , 1976Gwin , and 1984Wagemans 1988 and 1993 data; and Weston 1993 data. The other measurements, Weston 1984 and Weston 1988, should be normalized in an energy range overlapping with a measurement normalized at 0.0253 eV. The normalization performed by Weston in 1984 and 1988 gave average fission cross sections 3% to 4% smaller than the values recommended by the ENDF/B-VI standard committee in the energy range 100 to 1000 eV.…”

“…Recently [5], advancements made at Oak Ridge National Laboratory (ORNL) have allowed the treatment of large covariance matrices by using faster and larger computers with the improved version of SAMMY [6]. The evaluation performed at ORNL between 1985 and 1990 [1][2][3] relied, for the fission cross section, on the 1984 measurement of Weston et al [7] which was, on average 3% lower than the ENDF/B-VI standard cross sections [8] in the energy range 0.1 keV to 1.0 keV. New measurements were performed by Weston in 1991 [9] at ORNL and by Wagemans in 1993 [10] at Geel Linear Accelerator (GELINA), confirming the ENDF/B-VI standard values.…”

NEUTRON TOTAL CROSS SECTIONS OF 235U FROM TRANSMISSION MEASUREMENTS IN THE ENERGY RANGE 2 keV to 300 keV AND STATISTICAL MODEL ANALYSIS OF THE DATA

“…Parameters obtained from the SAMMY/FITACS fit of the experimental cross section in the energy range 2 keV to 200 keV. 27 Table 6 Experimental data: Blons 22 Migneco et al 23 % Wagemans et al 24 × Weston et al 26 Perez et al 28 …”

“…The shape of the solid line was obtained, in the present work, from an eye-guided fit of the experimental values, reproducing the structures observed in Beer data and in de Saussure data, at about 12% above the ENDF/B-VI evaluation. Since the current version of SAMMY/FITACS could not directly fit the experimental values of , an average capture cross section file CAP was created by multiplying the average fission cross sections of Weston et al 26 by the values of corresponding to the solid line of Fig. 5.…”