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Theoretical estimation of cross sections for neutron induced reactions
TL;DR: In this paper, an analytical model derived from nuclear reaction theory and having a simple functional form to demonstrate the quantitative agreement with the measured cross sections for neutron induced reactions is presented, where the neutron-nucleus total, reaction and scattering cross sections, for energies ranging from 5 to 700 MeV and for several nuclei spanning a wide mass range are estimated.
Abstract: We construct an analytical model derived from nuclear reaction theory and having a simple functional form to demonstrate the quantitative agreement with the measured cross sections for neutron induced reactions. The neutron-nucleus total, reaction and scattering cross sections, for energies ranging from 5 to 700 MeV and for several nuclei spanning a wide mass range are estimated. Systematics of neutron scattering cross sections on various materials for neutron energies upto several hundred MeV are important for ADSS applications. The reaction cross sections of neutrons are useful for determining the neutron induced fission yields in actinides and pre-actinides. The present model based on nuclear reaction theory provides very good estimates of the total cross section for neutron induced reaction.
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Journal Article•
TL;DR: In this paper, total cross sections for neutron scattering with energies between 10 and 600 MeV and from nine nuclei spanning the mass range from 6Li to 238U have been analyzed using a simple function of three parameters.
Abstract: Total cross sections for neutron scattering with energies between 10 and 600 MeV and from nine nuclei spanning the mass range from 6Li to 238U have been analyzed using a simple function of three parameters. The values of those parameters with which neutron total cross-section data are replicated vary smoothly with energy and target mass and may themselves be represented by functions of energy and mass.
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TL;DR: The total cross section and differential cross section for the inelastic scattering of neutrons are considered in this article, where it is assumed that the compound nucleus is sufficiently excited so that the statistical model may be applied.
Abstract: The total cross section and the differential cross section for the inelastic scattering of neutrons are considered. It is assumed that the compound nucleus is sufficiently excited so that the statistical model may be applied. If the statistical model may be applied as well to the residual nucleus, it is shown that the angular distribution of the inelastically scattered neutrons is isotropic. If only a few levels of the target nucleus can be excited, the angular distribution is anisotropic. Tables are provided which permit the calculation of the angular distribution if the incident and emergent neutron angular momenta are less than or equal to $3\ensuremath{\hbar}$. Examples of the evaluation of total cross sections are given, providing examples of the sensitivity of the results to the quantum numbers of the excited state.
1,609 citations
"Theoretical estimation of cross sec..." refers methods in this paper
...ucleus reaction cross sections are very useful for the theoretical calculations of Radioactive Ion Beam (Diamond 1999; Essabaa 2003) production. These can also be used for performing Hauser-Feshbach (Hauser and Feshbach 1952) calculations with Monte-Carlo simulations (Pace2 code 1984) to estimate the cross sections for neutron induced fission, evaporation residues or evaporation neutron multiplicities and for comparison of...
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TL;DR: In this article, the authors presented new phenomenological optical model potentials for neutrons and protons with incident energies from 1 keV up to 200 MeV, for (near-)spherical nuclides in the mass range 24⩽ A ⩽209 They are based on a smooth, unique functional form for the energy dependence of the potential depths, and on physically constrained geometry parameters.
1,373 citations
29 Sep 1995
TL;DR: In this article, a compact reliable and modular Cyclotron has been designed, which operates indefinitely in a closed cycle, namely the discharge of a fuel load, with the exception of fission fragments, is re-injected in the sub-critical unit with the addition of natural Thorium to compensate for the burnt fuel.
Abstract: "The EA operates indefinitely in a closed cycle, namely the discharge of a fuel load, with the exception of fission fragments, is re-injected in the sub-critical unit with the addition of natural Thorium to compensate for the burnt fuel. After many cycles an equilibrium is reached, in which the Actinide concentrations are the balance between burning and C incineration E. The fuel is used much more efficiently, namely the power obtained from 780 kg of Thorium is roughly the same as the one from 200 tons of native Uranium and a PWR (33 GW.day/t of burn-up). The probablility of a criticality accident is suppressed since the device operates at all times far away from it. Spontaneous convective cooling by the surrounding air makes a C melt-down E leak impossible. An EA module consists of a 1500 MWth unit with dedicated 1.0 GeV proton accelerator of 12.5 mA. A compact reliable and modular Cyclotron has been designed. A plant may be made of several such modules. For instance a cluster of three such modular units will produce about 2,000 MWe of primary electrical power. A relevant feature of our design is that it is based on natural convection to remove the heat generated inside the core. The EA is a large, passive device in which a proton beam is dumped and the heat generated by nuclear cascades is extracted without other major elements of variability. The delivered power is controlled exclusively by the current of the accelerator, The fuel needs no access during the whole burn-up and it may be kept sealed up as a non-proliferation safeguard measure. Contrary to Fusion, there are no major technologcal barriers. After = 700 years the radio-toxicity left is about 2000 times smaller than the one of an ordinary Pressurised Water Reactor (PWR) for the same energy. Geological storage (1e+06 years) is virtually eliminated or at least strongly reduced [<= 500 Ci/GWe.y) after 1000 years]. It could be furher reduced (<35 Ci) ""incinerating"" some of the nuclides. Radioactivity dose to individuals truncated to 10,000 years and due to operation is about1/330 of the one of PWR and about 1/33 of Coal burning."
463 citations
TL;DR: The isobaric spin dependence of the real part of the nuclear potential is investigated in this paper, which is expected theoretically from the action of Heisenberg forces and the exchange effects of other forces.
458 citations
TL;DR: Pulsed-beam time-of-flight techniques are used in a transmission measurement with a continuous spectrum of neutrons to determine neutron total cross sections with good precision up to 600 MeV, representing steps in the development of a neutron-nucleus optical potential at intermediate energy and important input for the clarification of isovector effects in the nucleon- nucleus interaction.
Abstract: Pulsed-beam time-of-flight techniques are used in a transmission measurement with a continuous spectrum of neutrons to determine neutron total cross sections with good precision up to 600 MeV. Neutrons are produced by spallation of the 800 MeV proton beam from the Los Alamos Meson Physics Facility accelerator incident on a thick, heavily shielded tungsten target at the Weapons Neutron Research facility at Los Alamos National Laboratory. Transmission measurements were completed for fifteen elements with 9\ensuremath{\le}A\ensuremath{\le}209 and three isotopically enriched samples of $^{40}\mathrm{Ca}$, $^{90}\mathrm{Zr}$, and $^{208}\mathrm{Pb}$. Principal features of the experiment are the intensity and time structure of the neutron source, tight collimation of the neutron beam line, good geometry, rapid cycling of the samples, stable electronics, and a small, fast neutron detector. Errors due to counting statistics were generally less than 1% for each of several hundred energy bins for each target. The measurements represent steps in the development of a neutron-nucleus optical potential at intermediate energy and important input for the clarification of isovector effects in the nucleon-nucleus interaction. The data also provide insight into the long-standing discussion of mean free paths of the nucleon in the nucleus.
135 citations