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Thursday, July 9, 2020 | History

2 edition of 14 Mev neutron-induced fission and 25 Mev photofission of 232-Th and 238-U. found in the catalog.

14 Mev neutron-induced fission and 25 Mev photofission of 232-Th and 238-U.

Lieven Hendrik Theofiel Gevaert

14 Mev neutron-induced fission and 25 Mev photofission of 232-Th and 238-U.

by Lieven Hendrik Theofiel Gevaert

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Published in Toronto .
Written in English

    Subjects:
  • Nuclear fission

  • Edition Notes

    ContributionsToronto, Ont. University.
    The Physical Object
    Pagination189 leaves.
    Number of Pages189
    ID Numbers
    Open LibraryOL18880654M

    The energy dependence of the relative yield of delayed neutrons and half-life of their precursor nuclei from U fission by – MeV neutrons is measured. In addition, the detector-blocking effect, which is due to the exposure of the detector to intense fluxes of high-energy neutrons, and the effect of the secondary neutron source D(d, n) 3 He, a reaction which occurs when a T(d, n) 4. Quantitative comparison of symmetric component in fission (to the total yield of fragments) for protons and neutrons, at the energy of incident nucleons up to about MeV, can be performed on the basis of the data obtained in the studies of fission of U by C.M. Zöller [Ph.D. thesis, TH Darmstadt, ] and C. Chung and J. Hogan [

    throughout. The matrix includes first-, second- and third-chance fission components and also includes the neutrons evaporated prior to fission in second- and third-chance fission. It has been calculated for 19 incident neutron energies ranging from to MeV. The model parameters used in the. Fission yields from the photofission of /sup /U with neutron . rays were measured at an effective excitation energy E/sub x/ = MeV. The mass distribution of the fission fragments was deduced by measuring yields of 19 mass chains with respect to /sup /Xe, whose cumulative yield was measured directly.

    Variations in the photofission cross section near ''threshold'' with initial kind of nucleus were investigated for seven spheroidal nuclei in the region of atomic numb 92, The photofission cross sections at the two discrete energies and Mev were determined for the following even-even nuclide. Nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei). The fission process often produces free neutrons and photons (in the form of gamma rays), and releases a large amount of nuclear physics, nuclear fission is either a nuclear reaction or a radioactive decay case of decay process is called spontaneous fission.


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14 Mev neutron-induced fission and 25 Mev photofission of 232-Th and 238-U by Lieven Hendrik Theofiel Gevaert Download PDF EPUB FB2

Despite the often difficult and time-consuming effort of performing experiments with fast (14 MeV) neutrons, these neutrons can offer special insight into nucleus and other materials because of the absence of charge.

14 MeV Neutrons: Physics and Applications explores fast neutrons in basic science and applications to problems in medicine, the environment, and security.

Drawing on his more. Abstract. Starting from measured provisional and post neutron mass distributions, the neutron emission curve, ν(m *), is calculated for the photofission of U and U with MeV bremsstrahlung, by applying a method similar to the method described by Terrell.

As a test of the procedure, the ν(m *) curve for the spontaneous fission of Cf and the thermal neutron induced fission Cited by: 4.

Neutron-Induced Fission of U, U, Th, Pu, Np, natPb and Bi Relative to U in the energy range MeV. In this work, we present results of fission calculations for proton-induced reactions on: a) Th at 27 and 63 MeV, b) U at 10, 30, 60 and MeV, and c) U at and : Vladimir Maslov.

Fission mass yields for molybdenum, ruthenium andpalladium andsilver, cadmium, and tin and in the 25 MeV bremsstrahlung beam fission of thorium and. The yields of various fission products in the 10 MeV bremsstrahlung-induced fission of Th, U and Pu were determined using a recoil catcher and off-line γ -ray spectrometric techniques.

From the yield data, mass yield distributions were obtained using charge distribution corrections. We analyzed mass-yield distributions from fission of U, U, U, U, and U with MeV neutrons to study the details of the fission distribution as a function of target mass number at a fairly low excitation energy.

Product yields for the photofission of^{} U and^{} U with MeV bremsstrahlung {} U,^{} U,^{} U, and^{} Th. Article. data of thermal to 14 MeV neutron-induced fission of.

A Muscovite mica track detector has been employed for the measurement of (a) fission cross-section, and (b) the angular anisotropy of the fission fragments emitted in fission of Pu, Pu, Pu, and Am induced by MeV neutrons.

A new approach has been tried to extract the above mentioned angular distribution information from experiments carried out in 2π-geometry instead. For neutron energies higher than MeV, the results of this experiment are slightly lower than the ENDF/B-VII.1 evaluation, but in agreement with the experiment of Tovesson et al.

() as well as Staples and Morley (). Finally, for energies above MeV, the results show consistency with the present evaluations.

A measurement of the U prompt fission neutron spectrum (PFNS) by the recoil proton method was performed at the Institute of Nuclear Physics and Chemistry, China. Details of the method, which include the calculation and validation of the response matrix, are presented.

The PFNS for U in the energy range 1–12 MeV, induced by thermal neutrons, was obtained. The reaction U(n,f) has been studied at IRMM at different incident neutron energies ranging from E n = to MeV.

The existence of vibrational resonances in the region of the threshold of the fission cross-section and the proton pairing effect should induce variations in the fission fragment properties. The fission fragment mass, mean total kinetic energy (TKE ¯) and angular. To the best of the author׳s knowledge, although product yields for neutron-induced fission of nuclides of interest (e.g.

Th, U, U, Pu) were well studied and are available in various nuclear databases, published photofission product yields are rather scarce. This survey is devoted to the investigation of fission probability by measuring photofission yields using a bremsstrahlung spectrum of the microtron with the relative measurement method in the region of energies from the threshold to the upper boundary of the fissility plateau (E MeV).The results were obtained using a unique technique for nineteen nuclei from Th to Cf.

For actinides irradiation, mm thick target Th and u with to 1 cm 2 size values for 148 MeV neutron-induced fission of U. photofission of U and U with MeV. Fission Product Yields for 14 MeV Neutrons on U, Uand Pu M. Mac Innes ∗, M.B.

Chadwick, and T. Kawano 1 1 Los Alamos National Laboratory, Los Alamos, NMUSA (Received 24 Junerevised received 22 September ; accepted 14 October ) We report cumulative fission product yields (FPY) measured at Los Alamos for 14 MeV neutrons on U.

Fission in natural U and man-made U and Pu is optimal at thermal incident neutron energies; whereas fission in U and Th requires neutron energies of at least 1 MeV. A more detailed treatment of nuclear fission was provided previously in Section Abstract.

We determined fission yields of xenon (m Xe, Xe, m Xe, Xe, Xe, and Xe) resulting from 14 MeV neutron induced fission of depleted uranium at the National Ignition Facility. Measurements begin approximately 20 s after shot time, and yields have been determined for nuclides with half-lives as short as tens of seconds.

= 25 meV the fission cross section σ f = b is huge ≈ times the geometrical cross section of U. One of the reasons for the huge σ f is the large neutron separation energy S n = MeV in U which exceeds the fission barrier B f = MeV.

For thermal neutrons the excitation energy E* of the compound is E* = S n > B f. The mass yield distribution for the 148 MeV neutron-induced fission of U has been measured radiochemically for 46 mass chains in the region A = 83– The absolute activities of each nuclide measured in this mass region were determined by gross beta counting and the cumulative fission yields were measured relative to 99 Mo.

The yields determined in this work are compared to all known. detection, assay, and nuclear safeguards applications. The fast neutron induced fissions of U, Th and Np produce complex fission spectra for many hours following irradiation, samples of U, Th and Np were irradiated with MeV neutrons in order to measure the beta-delayed gamma-ray spectra from induced fission.“The U and U to U fission cross section ratios in the neutron energy range 5–11 MeV,” in: Proc.

Int. Spec. Meeting on Transactinium Isotopes Nuclear Data, Uppsala (). 4.Abstract. Neutron induced reaction cross-sections at MeV were measured for Na, Mg, Al, K, P, Si, Cr, Mn, Fe, Co, Ni, Cu and Zn. High purity chemicals in powder form were irradiated at SAMES T low energy ion accelerator with neutron yield of about 10 10 /sec.