Showing papers in "Journal of Nuclear Energy in 1968"

TL;DR: The standard thermal flux has been produced by sources consisting of beryllium targets bombarded by a deuteron beam from a Van de Graaff accelerator, and has been reproducible to ± 0·1 per cent over a period of 6 months as discussed by the authors.

TL;DR: In this paper, the energy dependence of prompt v has been investigated for the neutron-induced fissions of 239Pu and 241Pu, at incident neutron energies between 4 and 14·8 MeV.

TL;DR: In this article, the authors measured neutron capture cross sections as a function of neutron energy between about 5 keV and 3 MeV for 41K, 55Mn, 85Rb, 89Y, 98Mo, 139La, 141Pr, 158Gd, 170Er, 175Lu and 176Yb.

TL;DR: In this paper, the available experimental data for the value of v for fissile and fertile isotopes is reviewed and the absolute determination of ν for 252Cf is discussed, since this provides the standard for normalizing the other values.

TL;DR: In this paper, a large liquid scintillator and a Linac-pulsed neutron source were used to measure high-resolution neutron total and capture cross sections from 0·01 to 10 eV.

TL;DR: In this paper, the theory of a real mixing cascade with constant cut number and with losses is developed, and the steady state distribution of the isotope concentrations in every stage, the total flow rate, the form factor and the number of stages for a desired final enrichment in the low concentration range are calculated.

TL;DR: In this paper, the cross section of the 235 U(n f) reaction has been measured with a high-energy resolution for neutrons between 6 eV and 3 keV, and the statistical distributions of Γ f, Γ γ and α have been studied.

TL;DR: The jN method as discussed by the authors is a new analytical approach which has emerged in the course of developing the multiple collision method and can be used to solve neutron transport problems for a bare sphere under the assumption that the scattering of neutrons is spherically symmetric in the laboratory system.

TL;DR: In this paper, an integral equation describing the propagation of a neutron wave along the axis of an infinite prism is derived, and the homogeneous part of this equation constitutes a dispersion relationship for the wavenumber as a function of frequency.

TL;DR: In this paper, the authors measured the thermalized neutron density decay in 17 graphite stacks, the B 2 value of which ranged from 2·-99 × 10 −3 cm −2 to 2530 × 10−3 cm−2 This range exceeds the theoretical B 2 ∗ by an amount greater than most work reported previously.

TL;DR: In this paper, the authors measured decay curves in BeO assemblies with bucklings in the range 1·93 × 10−2−5·34 × 10 −2cm−2 at times from immediately after the initial pulse to at least 4·5 msec after the pulse.

TL;DR: In this article, the capture cross-section shape of gold has been measured in the energy range 25-500 keV and normalized at 30 keV using a best fit value, which was obtained using a large liquid scintillator as a capture γ-ray detector and by means of a grey neutron detector which has a flat efficiency curve to measure the relative neutron flux.

TL;DR: The average number of prompt neutrons ν emitted per fission has been measured for the spontaneous fission of 340 Pu and 242 Pu relative to ν for spontaneous neutrons.

TL;DR: In this article, the total cross section of 240Pu has been measured with high resolution in the energy range 20 ev −5·7 KeV up to this energy 264 resonances were detected and analyzed with respect to Λn using the area program of Atta and Harvey.

TL;DR: In this paper, the decay constant of the neutron population was measured in BeO assemblies of various sizes, and particular attention was paid to the problem of room return, establishment of the asymptotic mode and the appearance of the continuous mode of decay.

TL;DR: In this paper, spectral indices have been measured by foil activation technique in a number of different D 2 O-moderated lattices in the Swedish zero power reactor RO and the pressurized exponential assembly TZ.

TL;DR: In this article, a new approach to energy-dependent neutron transport theory is described which treats the asymptotic solution of the Boltzmann equation exactly and approximates the spatial transient by the separable kernel model.

TL;DR: In this paper, an area analysis has been applied to the resonances observed, and the radiation widths of 32 resonances has been determined, yielding a mean value of 〈Λγ〉 (23·2 ± 2·0) meV.

TL;DR: In this article, a trans-form procedure is used to reduce the integral transport equation to a pseudo problem in slab geometry, and the analysis leads to a Fredholm integral equation for the only unknown expansion coefficient.

TL;DR: The half-life of 233 U has been found by two different specific activity determinations to be 1·553 ± 0·010 × 10 5 yr as mentioned in this paper, and the number of atoms of 233U was determined by mass analysis and the disintegration rate by low-geometry proportional counting.

TL;DR: In this article, the authors used the Placzek kernel with θD = 855°K to study the transient spectra in various beryllium oxide assemblies, following a pulse of fast neutrons.

TL;DR: The average number of prompt neutrons per fission for 252 Cf has been found to be 3·787 from independent measurements of the absolute fission rate and the absolute neutron output as mentioned in this paper.

TL;DR: In this paper, the fission cross sections of 233U, 235U and 239Pu relative to the neutron capture cross section of 59Co have been obtained by irradiating thin foils in a well-thermalized flux of reactor neutrons.

TL;DR: In this article, the efficiency of lithium-6 spectrometers in neutron beams has been calculated by means of a Monte Carlo technique and it is shown that the efficiency is, in general, not very well predicted by earlier calculations based on simpler models.

TL;DR: In this paper, the authors used two scattering models for beryllium: a simple, one-term degenerate kernel and a multiphonon kernel with Bhandari's σtr(E).

TL;DR: In this article, the spectrum at the center of a sub-critical vERA 7A assembly has been determined by the time-of-flight method in the range 100 eV 4·8 MeV using the Harwell 45 MeV electron linear accelerator to provide a pulsed source of fast neutrons.

TL;DR: In this paper, Langevin's technique is applied to two energy group space independent reactor model and the auto-and cross-correlation functions of the fluctuating sources associated with various random processes such as fission, capture, scattering, etc.

TL;DR: In this article, the time-dependent spatial flux distributions in five BeO assemblies covering the buckling range 0·9 × 10−2 to 2·15 × 10 −2cm−2 were measured.

TL;DR: In this paper, the reduced resonance integral of 55Mn was measured by a new method, using a conventional manganese sulphate bath containing several known concentrations of boron and employing an extrapolation technique.