Download or read book Theoretical Analyses of n Xn Reactions on Sup 235 U Sup 238 U Sup 237 Np and Sup 239 Pu for ENDF written by and published by . This book was released on 1991 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical analyses were performed of neutron-induced reactions on 235U, 238U, 237Np, and 239Pu between 0.01 and 20 MeV in order to calculate neutron emission cross sections and spectra for ENDF/B-VI evaluations. Coupled-channel optical model potentials were obtained for each target nucleus by fitting total, elastic, and inelastic scattering cross section data, as well as low-energy average resonance data. The resulting deformed optical model potentials were used to calculate direct (n, n(prime)) cross sections and transmission coefficients for use in Hauser-Feshbach statistical theory analyses. A fission model with multiple barrier representation, width fluctuation corrections, and preequilibrium corrections were included in the analyses. Direct cross sections for higher-lying vibrational states were calculated using DWBA theory, normalized using B(El) values determined from (d, d(prime)) and Coulomb excitation data, where available, and from systematics otherwise. Initial fission barrier parameters and transition state density enhancements appropriate to the compound systems involved were obtained from previous analyses, especially fits to charged-particle fission probability data. The parameters for the fission model were adjusted for each target system to obtain optimum agreement with direct (n, f) cross section measurements, taking account of the various multichance fission channels, that is, the different compound systems involved. The results from these analyses were used to calculate most of the neutron (n, n), (n, n(prime)), and (n, xn) cross section data in the ENDF/B/VI evaluations for the above nuclei, and all of the energy-angle correlated spectra. The deformed optical model and fission model parameterizations are described. Comparisons are given between the results of these analyses and the previous ENDF/B-V evaluations as well as with the available experimental data. 14 refs., 3 figs., 1 tab.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 840 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1991-10 with total page 1502 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1989 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1991 with total page 1768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Brief van Jacobus Tijken aan Didericus van Cruysselbergen 1728 written by and published by . This book was released on 1781 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Er bestaat een kans dat Bellamy financiële ondersteuning krijgt voor zijn studie uit de nalatenschap van Zwart.
Download or read book INIS Atomindeks written by and published by . This book was released on 1987 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parameters of Neutron Resonances sup 233 sup U sup 235 sup U and sup 239 sup Pu written by and published by . This book was released on 1970 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The total cross sections of 233U, 235U, and 239Pu, the fission and radiative capture cross sections of 235U, and 239Pu were measured by the time-of-flight method with time resolution of 40 and 55 ns/m using the JINR pulsed fast reactor. The liquid boron scintillation detector was used to detect the resonance neutrons in the measurements of the total cross sections by the transmission method. The measurements of the total cross sections and that of fission and radiative capture by the self-indication method were carried out using a large cadmium-loaded liquid scintillation detector.
Download or read book Improved sup 239 Pu n F Evaluation Below 20 MeV written by and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new improved covariance analysis of neutron-induced fission reactions on 239Pu has been conducted for neutron incident energies between 0.1 and 20 MeV. Plutonium-239 is a very important isotope in the US nuclear spent fuel stockpile, where it is considered as a waste and eventually a proliferation problem. Recently available experimental data sets, both absolute and in ratio to the standard 235U, have been included in this new study. A Bayesian inference approach has been used to infer cross sections and associated uncertainties and correlations. The evaluated errors are significantly reduced compared to the previous ENDF evaluation. The importance of the choice of the 235U (n, f) standard is revealed through a comparison with the most recent Japanese evaluation. Finally, we introduce new ideas and techniques that will be used in our forthcoming cross sections evaluations for other actinides of importance for ADS.
Download or read book Possible Viscosity Effects in Neutron induced Fission of sup 232 Th and sup 238 U Yields written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fission yields induced in the /sup 238/U(n, f) and /sup 232/Th(n, f) reactions were determined as a function of incident neutron energy (E/sub n/). The ratio of /sup 115/Cd-to-/sup 140/Ba yields as a function of E/sub n/ is analyzed by means of the equation Y/sub 1//Y/sub 2/ = exp(2(a/sub 1/(E/sub n/+E/sub 1/)/sup 1/2/ -2(a/sub 2/(E/sub n/+E/sub 2/)/sup 1/2/) to give values of a/sub i/, the level density parameter, and E/sub i/, the excitation energy for E/sub n/=0. The energies E/sub i/ are interpreted on the basis of the liquid drop model with shell and pairing corrections. Values are deduced for the energy dissipated by viscosity effects in the descent from the saddle point to the point where masses are fixed in the fissioning nucleus. These values are 1.7 MeV for /sup 232/Th(n, f) and 4.8 MeV for /sup 238/U(n, f). These values are consistent with the experimental observation that anti .nu./sub p/ is approx. 0.6 neutron greater for /sup 239/U fission than for /sup 233/Th fission and that strong odd--even (nucleon pairing) effects are found in the fragment total kinetic energy distribution for /sup 230/Th fission but not for /sup 234/U fission. The low dissipation energy values together with the low values of pre-scission kinetic energy deduced by Guet, et al., (Nucl. Phys. A134 (1971)1) indicate a shorter path from the saddle point of the fissioning nucleus to scission than is generally assumed in theoretical calculations. 31 references.
Download or read book Atlas Historico de Peru written by and published by . This book was released on 1867 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Delayed Neutron Equilibrium Spectra of U 235 U 238 and Pu 239 written by Eric S. Jacobs and published by . This book was released on 1991 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Data and Measurements Series written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The prompt-fission-neutron spectrum resulting from 239Pu fission induced by 0.55 MeV incident neutrons is measured from 1.0 to 10.0 MeV relative to that of 235U fission induced by the same incident-energy neutrons. The measurements employ the time-of-flight technique. Energy-dependent ratios of the two spectra are deduced from the measured values over the energy range 1.0 to 10.0 MeV. The experimentally-derived ratio results are compared with those calculated from ENDF/B-V, revision-2, and with results of recent microscopic measurements. Using the ENDF/B-V 235U Watt parameters for the 235U spectrum, the experimental measurements imply a ratio of average fission-spectrum energies of 239Pu/235U = 1.045 +- 0.003, compared to the value 1.046 calculated from ENDF/B-V, revision 2. 12 refs., 2 figs., 2 tabs.
Download or read book Evaluated Neutron Reaction Data for Uranium 238 written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods used to obtain evaluated neutron interaction and photon production data for 238U are described. (auth).
Download or read book Nuclear Data for Science and Technology written by Syed M. Qaim and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1041 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the Proceedings of the International Conference on Nuclear Data for Science and Technology held at Jillich in May 1991. The conference was in a series of application oriented nuclear data conferences organized in the past under the auspices of the Nuclear Energy Agency-Nuclear Data Committee (NEANDC) and with the support of the Nuclear Energy Agency-Committee on Reactor Physics (NEACRP). It was the fIrst international conference on nuclear data held in Germany, with the scientific responsibility entrusted to the Institute of Nuclear Chemistry of the Research Centre Jillich. The scientific programme was established by the International Programme Committee in consultation with the International Advisers, and the NEA and IAEA cooperated in the organization. A total of 328 persons from 37 countries and fIve international organizations participated. The scope of these Proceedings extends to a wide range of interdisciplinary topics dealing with measu rement, calculation, evaluation and application of nuclear data, with a major emphasis on numerical data. Both energy and non-energy related applications are considered and due attention is given to some fundamental aspects relevant to the understanding of nuclear data.
Download or read book STUDY OF SUP 237 NP PHOTONUCLEAR REACTIONS NEAR THRESHOLD INDUCED BY GAMMA RAYS FROM THERMAL NEUTRON CAPTURE written by L. P. Geraldo and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
