Download or read book Calculation of 239Pu n 2n Cross Section by the Subtraction and the Ratio Methods written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The 239Pu(n,2n) and the 235U(n,2n) cross section are estimated by applying unitarity in several approaches: a subtraction method and also by using a ratio approach that relates the above cross sections to the 238U(n,2n) cross section and the 239Pu(n,2n) cross section to the 235U(n,2n) cross section, respectively. Also, a self-consistent, simultaneous analysis of the cross section data of four nuclei, 239Pu, 235U, 238U and 232Th, was undertaken to evaluate the 239Pu(n,2n) cross section at 11 MeV.
Download or read book Alternate Approach to the 239Pu n 2n Cross Section written by and published by . This book was released on 2000 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using existing experimental data for neutron-induced total, elastic, inelastic, reaction and fission cross sections, as well as results from nuclear model calculations and evaluations from nuclear reaction data libraries, we derived an estimate for the cross sections for the 235U(n,2n) and 239Pu(n,2n) reactions for the neutron energy range from threshold to approximately 12 MeV. In effect, our approach is based on subtracting the fission and inelastic cross sections from the total reaction cross section where the difference is expected to yield the (n,2n) cross section. In addition to this subtraction approach, a ratio method and a differential method have also been explored. For 235U(n,2n), as a test case, we arrive at a cross section consistent with previous measurements, and for 239Pu(n,2n) we obtain a peak value of 400 " 60 mb for the incident neutron energy range of 10 (less-than or equal to) E{sub n} (less-than or equal to) 12 MeV.
Download or read book The 239 Pu n 2n 238 Pu Cross Section Preliminary Calculations written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary motivation for the present work is to provide theoretical values for the ratio of the partial 239Pu(n,2nxy)238Pu to total 239Pu(n,2n)238Pu cross section for several discrete gamma transitions. Results and conclusions of preliminary calculations from threshold to 20 MeV are presented. Calculations are based on theoretical models with parameters obtained from the literature or from our ad hoc systematics. Optical model cross sections and transmission coefficients were determined using the coupled-channels method. The calculations included a preequilibrium component followed by multiple particle and gamma-ray emissions. Fission competition was included at all stages of de-excitation. Suggestions for further verifications and possible improvements are provided.
Download or read book The 239 Pu n 2n 238Pu Cross Section written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary motivation for the present work is to provide theoretical values for the ratio of the partial 239Pu(n,2nx?)238Pu to total 239 Pu(n,2n)238Pu cross section for several discrete gamma transitions. Results and conclusions of preliminary calculations from threshold to 20 MeV are presented. Calculations are based on theoretical models with parameters obtained from the literature or from our ad hoc systematics. Optical model cross sections and transmission coefficients were determined using the coupled-channels method. The calculations included a preequilibrium component followed by multiple particle and gamma-ray emissions. Fission competition was included at all stages of de-excitation. Suggestions for further verifications and possible improvements are provided.
Download or read book 239Pu n 2n 238Pu Cross Section Inferred from IDA Calculations and GEANIE Measurements written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the latest 239Pu(n,2n)238Pu cross sections inferred from calculations performed with the nuclear reaction-modeling code system, IDA, coupled with experimental measurements of partial [gamma]-ray cross sections for incident neutron energies ranging from 5.68 to 17.18 MeV. It is found that the inferred 239Pu(n,2n)238Pu cross section peaks at E{sub inc} ≈ 11.4 MeV with a peak value of approximately 326 mb. At E{sub inc} ≈ 14 MeV, the inferred 239Pu(n,2n)238Pu cross section is found to be in good agreement with previous radio-chemical measurements by Lockheed. However, the shape of the inferred 239Pu(n,2n)238Pu cross section differs significantly from previous evaluations of ENDL, ENDF/B-V and ENDF/B-VI. In our calculations, direct, preequilibrium, and compound reactions are included. Also considered in the modeling are fission and [gamma]-cascade processes in addition to particle emission. The main components of physics adopted and the parameters used in our calculations are discussed. Good agreement of the inferred 239Pu(n,2n)238Pu cross sections derived separately from IDA and GNASH calculations is shown. The two inferences provide an estimate of variations in the deduced 239Pu(n,2n)238Pu cross section originating from modeling.
Download or read book Evaluation of the 239Pu n 2n Integrated Cross Section written by and published by . This book was released on 2001 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, new cross section measurements by the GEANIE collaboration have been published for 239Pu(n, 2n[gamma]) [Ber00] and 235U(n, 2n[gamma]) [You00] from threshold to 20 MeV. When combined with nuclear reaction calculations [Che00, Cha99, Cha01], these measurements provide the most accurate information available on the shape and magnitude of the 239Pu(n, 2n) cross section for incident neutron energies, E{sub n} ≈
Download or read book Estimating Reaction Cross Sections from Measured Gamma Ray Yields written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A procedure is presented to deduce the reaction-channel cross section from measured partial [gamma]-ray cross sections. In its simplest form, the procedure consists in adding complementary measured and calculated contributions to produce the channel cross section. A matrix formalism is introduced to provide a rigorous framework for this approach. The formalism is illustrated using a fictitious product nucleus with a simple level scheme, and a general algorithm is presented to process any level scheme. In order to circumvent the cumbersome algebra that can arise in the matrix formalism, a more intuitive graphical procedure is introduced to obtain the same reaction cross-section estimate. The features and limitations of the method are discussed, and the technique is applied to extract the 235U (n,2n) and 239Pu(n,2n) cross sections from experimental partial [gamma]-ray cross sections, coupled with (enhanced) Hauser-Feshbach calculations.
Download or read book Capture Gamma ray Spectroscopy And Related Topics Proceedings Of The Eleventh International Symposium Cgs 11 written by Jan Kvasil and published by World Scientific. This book was released on 2003-06-02 with total page 895 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a collection of invited talks, oral contributions and poster contributions devoted to advances in gamma-ray spectroscopy of various capture reactions. In agreement with the trend of previous meetings in the series, the symposium paid special attention to theoretical and experimental studies of nuclear structure at low energies and to nuclear astrophysics. Among the other topics covered are: statistical properties of nuclei and other quantum many-body systems, fundamental physics, nuclear data, practical application of capture reactions, and new techniques and facilities for capture gamma-ray spectroscopy.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calculation of 239pu n N Cross Sections to 5 MeV written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Calculations of the 239Pu(n, n') cross section and other relevant cross sections for incident neutron energies of up to 5 MeV are presented. Two components of the 239Pu(n, n') cross section are included. The direct contribution to the 239Pu(n, n') cross section is computed by the coupled-channel optical model. The compound component is calculated by a Hauser-Feshbach statistical treatment. Fission and [gamma]-cascade processes are considered as competing channels in the compound-decay process. Whenever possible, calculations are compared with experimental data and evaluations.
Download or read book Proceedings of the Eleventh International Symposium Capture Gamma Ray Spectroscopy and Related Topics written by Pavel Cejnar and published by World Scientific. This book was released on 2003 with total page 895 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a collection of invited talks, oral contributions and poster contributions devoted to advances in gamma-ray spectroscopy of various capture reactions. In agreement with the trend of previous meetings in the series, the symposium paid special attention to theoretical and experimental studies of nuclear structure at low energies and to nuclear astrophysics. Among the other topics covered are: statistical properties of nuclei and other quantum many-body systems, fundamental physics, nuclear data, practical application of capture reactions, and new techniques and facilities for capture gamma-ray spectroscopy. Contents: Nuclear Structure; Nuclear Reactions; Nuclear Astrophysics; Statistical Properties of Nuclei; Experimental Facilities; Nuclear Data; Applications; Fundamental Physics. Readership: Graduate students and researchers in nuclear physics.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1972 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Report on 238Pu n X Surrogate Cross Section Measurement written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this year's effort is to measure the 238Pu(n, f) and 238Pu(n,2n) cross section from 100 keV to 20 MeV. We designed a surrogate experiment that used the reaction 239Pu(a, a(prime)x) as a surrogate for 238Pu(n, x). The experiment was conducted using the STARS/LIBERACE experimental facility located at the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory in January 2010. A description of the experiment and status of the data analysis is given. In order to obtain a reliable 238Pu(n, x) cross section we designed the experiment using the surrogate ratio technique. This technique allows one to measure a desired, unknown, cross section relative to a known cross section. In the present example, the 238Pu(n, x) cross section of interest is determined relative to the known 235U(n, x) cross section. To increase confidence in the results, and to reduce overall uncertainties, we are also determining the 238Pu(n, x) cross section relative to the known 234U(n, x) cross section. The compound nuclei of interest for this experiment were produced using inelastic alpha scattering. For example, 236U(a, a(prime)x) served as a surrogate for 235U(n, x); analogous reactions were considered for the other cross sections. Surrogate experiments determine the probabilities for the decay of the compound nuclei into the various channels of interest (fission, gamma decay) by measuring particle-fission (p-f) or particle?gamma (p?g) reaction spectra. By comparing the decay probabilities associated with the unknown cross section to that of a known cross section it is possible to obtain the ratio of these cross sections and thus determine the unknown, desired cross section.
Download or read book Measurement of the Ratio of the n 2n Cross Section of 29Cu62 to 30Zn63 written by Shean-Cheng Tsou and published by . This book was released on 1973 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Passive Nondestructive Assay of Nuclear Materials written by Doug Reilly and published by . This book was released on 1991 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Photoneutron Sources written by B. W. Sargent and published by . This book was released on 1946 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook on Nuclear Activation Data written by International Atomic Energy Agency and published by . This book was released on 1987 with total page 838 pages. Available in PDF, EPUB and Kindle. Book excerpt: The contents of this Handbook are, in general, similar to IAEA Technical Reports Series No. 156, Handbook on Nuclear Activation Cross-Sections, published in 1974. However, there are several important changes in this version, besides the inclusion of more recent data. For example, in Part 1, all the necessary information on standard reference data is now included.
