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 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 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 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 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 Evaluation of the 239Pu n 2n Integrated Cross Section written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract not provided.
Download or read book Handbook of Nuclear Chemistry written by Attila Vértes and published by Springer Science & Business Media. This book was released on 2010-12-10 with total page 3693 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revised and extended 6 volume handbook set is the most comprehensive and voluminous reference work of its kind in the field of nuclear chemistry. The Handbook set covers all of the chemical aspects of nuclear science starting from the physical basics and including such diverse areas as the chemistry of transactinides and exotic atoms as well as radioactive waste management and radiopharmaceutical chemistry relevant to nuclear medicine. The nuclear methods of the investigation of chemical structure also receive ample space and attention. The international team of authors consists of scores of world-renowned experts - nuclear chemists, radiopharmaceutical chemists and physicists - from Europe, USA, and Asia. The Handbook set is an invaluable reference for nuclear scientists, biologists, chemists, physicists, physicians practicing nuclear medicine, graduate students and teachers - virtually all who are involved in the chemical and radiopharmaceutical aspects of nuclear science. The Handbook set also provides further reading via the rich selection of references.
Download or read book Radionuclides written by Javier Guillén Gerada and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We live in a radioactive world. This fact poses some questions: where does it come from?; how much radioactivity is there?; how can it affect human health? The radioactive content surrounding us has different source terms depending on which radionuclides are considered. According to this, they can be classified into anthropogenic (or man-made) radionuclides and naturally occurring ones. In this book, the authors discuss the health hazards, medicinal benefit and uses of radionuclides.
Download or read book Radioactive Particles in the Environment written by Deborah Oughton and published by Springer. This book was released on 2009-07-31 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive particles have been released to the environment from a number of sources, including nuclear weapon tests, nuclear accidents and discharges from nuclear installations. Particle characteristics influence the mobility, biological uptake and effects of radionuclides, hence information on these characteristics is essential for assessing environmental impact and risks. This publication presents a series of papers covering sources and source term characterisation, methodologies for characterizing particles, and the impact of particles on the behaviour of radioactive particles in the environment. Sources covered include the Chernobyl accident, nuclear weapons accidents at Thule and Palomares accident, the discharges from Dounreay and Krashnoyarsk, and depleted uranium in Kosovo and Kuwait. The overall aim is that an increased understanding of particle characteristics and behavior will help to reduce some of the uncertainties in environmental impact and risk assessment for particle contaminated areas.
