Fission Neutron Spectrum ofU235

Abstract

The neutron spectrum associated with the fission of U 235 induced by slow neutrons has been remeasured from 0.18 to 12 Mev. Two different experimental techniques were employed in this measurement: (1) the time-of-flight method covering the energy range from 0.18 to 2.7 Mev, and (2) the photographic plate method encompassing the energy range from 0.35 to 12 Mev. The combined results of these measurements fit the relation, N{E)^Ke^E' QMh sinh[(2.29£)»], where N(E) is the neutron flux, E is the neutron energy in Mev and K is a constant. The simpler expression, N(E) =KEh~°-17bE , also fits the data well for neutron energies below 9 Mev.f This work was performed under the auspices of the U. S.

Simulation of Energy-Range Relation for Protons Impacting on N-4 Nuclear Emulsion

“…83 data points have been selected from the simulation results that covering the energy range from 10keV to 14MeV to be used for analysis. The cubic polynomial is expressed as formula (2)…”

“…It has been amongthe earliestparticle detectors used in high-energy physics and has inherent advantages when detecting neutrons in high energy [1]. Neutrons can be detected via recoil proton tracks in the nuclear emulsion and the neutron energy spectrum can then be determined from length distribution of the tracks [2,3]. To determine the energy of each incident neutron with respect to the proton recoil trajectory, the usual procedure is to accept proton recoils within a given angular criteria, measure the projection in the plane of the emulsion of the ranges of the recoil protons, and make an average correction to the deduced neutron energies.When using the nuclear recoil method to detect neutrons, most of the energy of the neutrons are passed to the recoil protons.Especially when the incident neutronsimpact on thenuclear emulsion planeperpendicularly, energy of the recoil protons roughly equal to that of the incident neutrons.…”

PWR Facility Dose Modeling Using MCNP5 and the CADIS/ADVANTG Variance-Reduction Methodology

“…A number of researchers seem to have proposed this shape, which was probably first reported in the literature by Watt, when he documented his measurements on fission-neutron spectra. Cranberg et al (1956), who reported on extended measurements some years later, also discuss this representation of the neutron spectrum. The Watt spectrum can be described by…”

GAS RELEASE AND COMPRESSION PROPERTIES IN BERYLLIUM IRRADIATED AT 600 AND 750$sup 0$C.

“…of each reaction is proportional to the product of the reaction cross section, o, and the number of incident neutrons, n, at that energy. The value of n was taken from Cranberg et al [12] The effective range of o.-particles with energy of 0.32 MeV was determined, and the helium released within this distance of the surface of the beryllium was compared with the total gas produced and measured.…”