Investigation of fast neutron interaction with235U

Abstract

The angular distribution of neutrons emitted by elastic, inelastic and fission processes on 23sU were measured at the incident neutron energies of 1.5, 1.9, 2.3, 4.0, 4.5, 5.0 and 5.5 MeV using nanosecond time-of-flight technique. The differential elastic scattering cross sections and their angular distributions at all the seven energies are presented. The total elastic scattering cross sections, angle and energy integrated cross sections for the inelastically scattered neutrons in energy bands of 200 keV, fission cross sections and the angular distributions of fission neutrons were extracted at 1.5, 1.9 and 2.3 MeV incident neutron energies. The energy distributions of the prompt fission neutrons and of the inelastically scattered neutrons are given at the incoming neutron energies of 1.5, 1.9 and 2.3 MeV; and the average fission neutron energies and the inelastic neutron evaporation temperatures were also evaluated at these energies.

Criticality experiments and benchmarks for cross section evaluation: the neptunium case

“…Knitter used a Van de Graaff accelerator to produce mono-energetic neutron beams of 1.5, 1.9 and 2.3 MeV [9] in order to measure the inelastic scattering cross section of 235 U. The kinetic energy loss of neutrons was integrated over 200 keV-wide bands from 0.4 MeV to the incident energy minus 0.5 MeV.…”

Prompt fission neutron spectra from fission induced by 1 to 8 MeV neutrons onU235andPu239Noda1, Haight2, Nelson3 et al. 2011Phys. Rev. C281220View full textAdd to dashboardCite

“…Although the model is used for these and other actinides over a wide range of incident neutron energies, only a few experiments have been performed above 1 MeV. Boykov et al [9] measured the prompt fission-neutron spectra at 2.9 and 14.7 MeV for 235 U. Knitter et al measured the fission neutron spectrum for fission induced by neutrons of 1.5, 1.9, and 2.3 MeV neutrons on 235 U [10] and 0.215 MeV neutrons on 239 Pu [11]. Staples et al [12] measured prompt fission neutron spectra at 0.5, 1.5, 2.5, and 3.5 MeV for 235 U and 239 Pu.…”

“…The above-referenced data are based on monoenergetic neutron sources, for example, those based on DD and DT reactions [9], the P+T reaction [10], and the 7 Li(p,n) reaction [11,12]. Generally these monoenergetic neutron sources are intense, but for such neutron facilities, each incident neutron energy corresponds to a separate experiment with potential systematic effects from possible instabilities in the detectors and electronics.…”

“…Generally these monoenergetic neutron sources are intense, but for such neutron facilities, each incident neutron energy corresponds to a separate experiment with potential systematic effects from possible instabilities in the detectors and electronics. Another limitation of some of the previous measurements [10][11][12] is that thick samples of actinides were used and only fission neutrons above the incident neutron energy were detected. Our approach is to address both of these issues with the use of a continuous ("white") source of incident neutrons and an ionization chamber to detect fissions.…”

Evaluation of the 235U prompt fission neutron spectrum including a detailed analysis of experimental data and improved model information

“…Experimental data and uncertainties: The ten experimental data sets [8][9][10][11][12][13][14][15][16] shown in Fig. 1 are considered for the evaluation.…”