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An Analysis Of Fission Product Gamma Spectra
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Book Synopsis Determination of Np239, "total Fissions", Mo99, and Ce141 in Fission Product Mixtures by Gamma-ray Scintillation Spectrometry by : L. G. McIsaac
Download or read book Determination of Np239, "total Fissions", Mo99, and Ce141 in Fission Product Mixtures by Gamma-ray Scintillation Spectrometry written by L. G. McIsaac and published by . This book was released on 1956 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Analysis of Fission Product Gamma Spectra by : Gene David Holter
Download or read book An Analysis of Fission Product Gamma Spectra written by Gene David Holter and published by . This book was released on 1977 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The gamma contribution to reactor afterheat depends on gamma energy since high-energy commas are more likely to escape from tilt. fuel. The objective of this work is to investigate the gamma-energy spectrum of a pure U-235 fission reactor. Fission-product nuclides are first listed in order' of importance as contributors to total gamma energy at various times after shutdown. In particular, lists are drawn up using LNDF/B-IV data for 1, 10, 100, 1,000, and 10,000 seconds after a fission burst and after an operating time of 24 hours. Luclides from these lists are then compared with nuclides from a magnetic tape entitled "radioactive Nuclide Decay Data -File-CWR 17-74" by Charles W. Reich of the Aerojet Nuclear Corporation. The Reich tape provides little data about important gamma contributors in the early stages after short irradiation times. A simrlified approach is chosen to estimate the gamma spectra of nuclides without Reich data. That is 1 nuclides in the Reich. tape are sorted into "boxes" (collections of nuclides) on the basis of simple nuclear systematics and the "box" averages are assumed to represent the nuclides without Reich data. Isomeric states, nuclides with less than ten gamma spectral lines, and nuclides with atomic mass numbers above 200 are generally excluded from sorting. Each sorting into boxes is done in two ways: (1) by the "absolute-energy" method, where gamma spectra are split into "energy groups" of fixed intervals, such as 250 keV, and (2) by the "adjusted-energy" method, where the gamma spectrum of each nuclide is split into "energy groups" found by dividing that nuclide's Q value by a fixed number, such as ten. The second method is preferred. In a "zeroeth" sorting, all nuclides are put into just one box. In the first sorting, nuclides are put into four boxes (even-even, even-odd, odd-even, and odd-odd) based on the oddness or evenness of proton number and of neutron number. In the second sorting, nuclides are put into four boxes (1 -Z magic, N-0 magic, 0-Z magic, and 0-0 magic) on the basis of distance from the magic numbers 28, 50, 82, and 126. A nuclide is deemed "N-magic" (for its neutron number) or "Z-magic" (for its proton number) according to its "closeness" to a magic number, where "closeness" is defined by a bandwidth around each magic number. In the third sorting, nuclides are put into one of four boxes according to distance from beta stability, which is equal to the number of consecutive beta-minus decays required to reach a stable nuclide (or a very longlived nuclide). In the fourth sorting, nuclides are put into two boxes (positive and negative) on the basis of the parity of the ground states. For each box, an average spectrum (normalized to 100%) is computed to indicate the percentage of gammas contributed by each energy group. Also calculated for each energy group is its standard deviation from the average spectrum. Since the standard deviations are usually too large to be of value, "composite" spectra are created by weighting the average spectra from various individual sortings. In the "tri-composite" case, each of three factors (odd-evenness, distance from magic number, and distance from beta stability) are used in several combinations of weighting. In the "optimum" combination (where the sum of the squares of the standard deviations is minimized), odd-evenness has about twice the weight of distance from magic number, while distance from beta stability is insignificant. Finally, the optimized composite spectra are used to provide estimates of actual gamma spectra at various instants after reactor shutdown. several operating histories prior to shutdo, cm are considered for purposes of comparison.
Book Synopsis An Analysis of Calculated and Measured Fission Product Activities by : J. E. Watson
Download or read book An Analysis of Calculated and Measured Fission Product Activities written by J. E. Watson and published by . This book was released on 1964 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: Calculations and measurements of delayed beta and gamma activities and spectra following nuclear fission are presented. There is good agreement between various calculations and measurements of gamma activity and spectra of U-235 fission products. There is a degree of agreement in calculated and measured beta activity. U-235 fission product beta and gamma activities are integrated over time to determine the total number of betas and the total gamma energy emitted per fission. Analysis of various information reveals that: (1) Gamma activity and spectra following fission of U-235 by thermal neutrons coincide with that of fission of U-235 by fission spectrum neutrons. (2) Gamma activities of U-235 fission products and Pu-239 fission products are identical within limits of experimental error. (3) Initial beta and gamma activities of U-238 fission products are approximately a factor of 2 higher than for U-235 fission products.
Book Synopsis Determination of Independent and Cumulative Fission Product Yields with Gamma Spectrometry by : Kenneth Joseph Dayman
Download or read book Determination of Independent and Cumulative Fission Product Yields with Gamma Spectrometry written by Kenneth Joseph Dayman and published by . This book was released on 2015 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fission product yields are vital to nuclear forensics and safeguards missions, especially active interrogation technologies and post-event forensic response. However, there have been limited experimental measurements performed to date, and the majority of the existing data is based on nuclear models. Updates to the nuclear data such as branching ratios have been made over time, the need for new measurements has come to light as datasets are no longer self-consistent and there are significant discrepancies between datasets. A method has been developed to determine independent and cumulative fission product yields using Bayesian inference. The methodology combines gamma-ray spectrometry, nuclide transmutation and burnup modeling, numerical optimization, and Monte Carlo sampling. The developed convex optimization was solved using three solvers: the Nelder-Mead Simplex direct search, the Levenberg-Marquardt algorithm, and Newton's Method. Sources of uncertainty were treated using sensitivity coefficient estimation with perturbation analysis as well as Monte Carlo sampling to determine uncertainty in the estimated values for fission product yields and produce uncertainty budgets. Each part of the analysis method was verified using controlled data analysis experiments with known results and then validated with two experiments. The Levenberg-Marquardt algorithm is the fastest and most reliable approach to optimization of three algorithms tested, and Monte Carlo sampling better treated uncertainty by explicitly treating correlations between input parameters, accounting for higher-order effects neglected by first-order sensitivity coefficients, and providing entire probability distributions for results. Thermal irradiations were performed at The University of Texas to produce fission products by bombarding naturally enriched U3O8 in a thermal neutron field provided by the 1.1 MW TRIGA reactor's thermal pneumatic transfer irradiation facility. Eleven long-lived fission products were identified and quantified using a series of gamma-ray spectra collected of the sample after the end of irradiation. Molybdenum-99 was used as an internal standard to estimate the time-averaged neutron flux incident on the sample, resulting in a value of (2.26 ± 0.24) × 1010 cm−2s−1, which agrees with prior operator experience. Fission product yields for the other ten identified radionuclides were estimated. The results agreed reasonably with literature values. Biases relative to literature values are positive and negative with an average bias of 6.3%, and the absolute relative error is 9.7%, suggesting that no systematic biases or major sources of untreated error were present in the analysis. Scientists at Pacific Northwest National Laboratory irradiated a 220 mg 235U foil with greater than 99% enrichment in a 14.1 MeV neutron field using a neutron generator and collected list-mode gamma-ray counting data. These data were parsed at The University of Texas to create sets of twenty-minute and twelve-hour gamma-ray spectra that were used to identify and quantify short- and long-lived fission products, respectively. In total, nineteen fission products with half-lives ranging from 3.2 minutes to 64.0 days were studied. The neutron flux of (2.36 ± 0.11) × 108 cm−2s−1 was estimated using 99Mo as an internal standard, and the determined value was used to calculate fission product yields of the remaining fission products. Determined values differ greatly from literature values; however, literature values for 14.1 MeV neutrons are less studied, especially for short-lived nuclides, and gamma-ray measurements of long-lived fission products are unreliable due to the small number of fissions that occurred during irradiation. Despite the limitations of the data, the results of the analyses are positive and confirm the viability of the developed methodology for further fission product yield analysis, as well as other nuclear data measurements, and application to nuclear forensics and safeguards inverse problems.
Book Synopsis Applied Gamma-Ray Spectrometry by : C. E. Crouthamel
Download or read book Applied Gamma-Ray Spectrometry written by C. E. Crouthamel and published by Elsevier. This book was released on 2013-10-22 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied Gamma-Ray Spectrometry covers real life application of the gamma-ray and the devices used in their experimental studies. This book is organized into 9 chapters, and starts with discussions of the various decay processes, the possible interaction mechanisms of gamma radiation with matter, and the intrinsic and extrinsic variables, which affect the observed gamma-ray and X-ray spectra. The subsequent chapters deal with the properties and fabrication of scintillation detectors, semiconductor detectors, and proportional gas counters. These chapters present some of the most widely utilized applications of these detectors, with a particular emphasis to the activation analysis. These topics are followed by reviews of the description of basic equipment, such as amplifiers, analyzers, special spectrometer arrangements, and detector shielding. Other chapters describe energy and time resolution and quantitative calibration. The quantitative and qualitative interpretation of the spectra is also explained, along with the calibration of the detectors. The last chapter considers the analytical applications of gamma-ray and X-ray spectrometry in tracer studies, activation analysis, fission product studies, and X-ray fluorescence analysis. This book will be of value to analytical chemists and analytical chemistry researchers.
Book Synopsis Fission Product Decay Gamma Energy Spectrum by : John D. Moteff
Download or read book Fission Product Decay Gamma Energy Spectrum written by John D. Moteff and published by . This book was released on 1953 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Early Time Decay of Fission Product Mixtures by : P. Zigman
Download or read book Early Time Decay of Fission Product Mixtures written by P. Zigman and published by . This book was released on 1959 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Determination of Fission Product Yields of 235U Using Gamma Ray Spectroscopy by : Christopher Hing Lu
Download or read book Determination of Fission Product Yields of 235U Using Gamma Ray Spectroscopy written by Christopher Hing Lu and published by . This book was released on 2012 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is important to have a method of experimentally calculating fission product yields. Statistical calculations and simulations produce very large uncertainties. Experimental calculations, depending on the methods used, tend to produce lower uncertainties. This work set up a method to calculate fission product yields using gamma ray spectroscopy. In order to produce a method that was theoretically sound, a simulation was set up using OrigenArp to calculate theoretical concentrations of fission products from the irradiation of natural uranium. From these concentrations, the fission product yields were calculated to verify that they would agree with expected values. Moving forward in the work, the total flux at the point of irradiation, in the pneumatic transfer system, was calculated and determined to be 3.9070E+11 ± 6.9570E+10 n/cm2/s at 100 kW. Once the flux was calculated, the method for calculating fission product yields was implemented and yields were calculated for 10 fission products. The yields calculated were in very good agreement (within 10.04%) with expected values taken from the ENDF-349 library. This method has strong potential in nuclear forensics as it can provide a means for developing a library of experimentally-determined fission product yields, as well as rapid post-nuclear detonation analysis.
Book Synopsis Fission Product Decay Gamma Energy Spectrum by : John Moteff
Download or read book Fission Product Decay Gamma Energy Spectrum written by John Moteff and published by . This book was released on 2013-01 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gamma-ray Spectra of the Products of Fast Neutron Fission of U235 and U238 at Selected Times After Fission by : Leland R. Bunney
Download or read book Gamma-ray Spectra of the Products of Fast Neutron Fission of U235 and U238 at Selected Times After Fission written by Leland R. Bunney and published by . This book was released on 1966 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental measurements of the gamma-ray pulse height distributions due to the products of fast-neutron-induced fission of Uranium-235 and Uranium-238 are presented. The measurements were made at nine selected times after fission from 15 minutes to 3 days. Irradiation times and counting intervals were chosen to minimize saturation and decay effects. The experimental data were used to calculate 100 energy bin distributions of the absolute number of photons/fission-sec. by means of absolute calibrations of the collimated NaI(T1) detector. The number of fissions in each sample was determined radiochemically. Machine computation was used extensively.
Book Synopsis Gamma Radiation from Fission Products by : Ronald B. Drinkwater
Download or read book Gamma Radiation from Fission Products written by Ronald B. Drinkwater and published by . This book was released on 1974 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytical study was made to determine the gamma radiation produced by the products of a fission device. The radiation during times from .10 sec to 2 min after fission was of special interest. Fission yield data were gathered for 5 fuels (fission spectraU235, U238, and Pu239; and 14 MeV spectra U235 and U238). Decay data were gathered for the fission products of these fuels. A computer program was written to process the data which produced quantitative energy and number rates of interest in fission product gamma radiation analysis. (Modified author abatract).
Book Synopsis Gamma-ray Spectrum Data Library of Fission Product Nuclidesandits Assessment by : Jun-ichi Katakura
Download or read book Gamma-ray Spectrum Data Library of Fission Product Nuclidesandits Assessment written by Jun-ichi Katakura and published by . This book was released on 1988 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fission Product Gamma Spectra by : Edward Thornton Jurney
Download or read book Fission Product Gamma Spectra written by Edward Thornton Jurney and published by . This book was released on 1979 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Generalized Method for Fissile Material Characterization Using Short-lived Fission Product Gamma Spectroscopy by : Justin Richard Knowles
Download or read book A Generalized Method for Fissile Material Characterization Using Short-lived Fission Product Gamma Spectroscopy written by Justin Richard Knowles and published by . This book was released on 2016 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterizing the fissile content of nuclear materials is of particular interest to the safeguards and nuclear forensics communities. Short-lived fission product gamma spectroscopy offers a significant reduction in analysis time and detection limits when compared to traditional non-destructive assay measurements. Through this work, a fully generalizable method that can be applied to variations in fissile compositions and neutron spectra was developed for the modeling and measurement of short-lived fission product gamma-rays. This method uses a 238-group neutron flux that was characterized for two pneumatic tube positions in the High Flux Isotope Reactor using flux monitor irradiations. This flux spectrum was then used in determining theoretical fission product photopeak emission rates per unit fissile mass during measurement. From these theoretical values, a mathematical method for characterizing the fissile material within a sample was established and demonstrated in several cases. The Oak Ridge National Laboratory's High Flux Isotope Reactor and Neutron Activation Analysis Laboratory provided optimal conditions to conduct high-flux irradiations with short decay periods. Experiments with samples containing nanogram quantities of 235U, 233U, and 239Pu were accurately characterized through measurement of short-lived fission product photopeaks. These measured photopeaks were combined with the simulated theoretical production rates to construct an overdetermined system of linear equations. Once this overdetermined system was solved, it showed high accuracy in quantifying fissile content. These experiments resulted in errors less of than 10% for quantification of fissile material in single element samples, two element mixed samples, and varying enrichments of uranium on IAEA swipes.
Book Synopsis Measurement/Evaluation Techniques and Nuclear Data Associated with Fission of 239Pu by Fission Spectrum Neutrons by :
Download or read book Measurement/Evaluation Techniques and Nuclear Data Associated with Fission of 239Pu by Fission Spectrum Neutrons written by and published by . This book was released on 2010 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Panel was chartered to review and assess new evaluations of work on fission product data, as well as the evaluation process used by the two U.S. nuclear weapons physics laboratories. The work focuses on fission product yields resulting from fission spectrum neutrons incident on plutonium, and includes data from measurements that had not been previously published as well as new or revised fission product cumulative yield data, and related quantities such as Q values and R values. This report documents the Panel's assessment of the work presented by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL). Based on the work presented we have seven key observations: (1) Experiments conducted in the 1970s at LANL, some of which were performed in association with a larger, NIST-led, program, have recently been documented. A preliminary assessment of this work, which will be referred to in this document as ILRR-LANL, shows it to be technically sound. (2) LLNL has done a thorough, unbiased review and evaluation of the available literature and is in the process of incorporating the previously unavailable LANL data into its evaluation of key fission product yields. The results of the LLNL effort, which includes a preliminary evaluation of the ILRR-LANL data, have been documented. (3) LANL has also conducted an evaluation of fission product yields for fission spectrum neutrons on plutonium including a meta-analysis of benchmark data as part of a planned upgrade to the ENDF/B compilation. We found that the approach of using meta-analysis provides valuable additional insight for evaluating the sparse data sets involved in this assessment. (4) Both laboratories have provided convincing evidence for energy dependence in the fission product yield of 147Nd produced from the bombardment of 239Pu with fission spectrum neutrons over an incident neutron energy range of 0.2 to 1.9 MeV. (5) Consistent, complete, and explicit treatment of both systematic and statistical uncertainties, including correlations, are critical to the assessment of both the experimental measurements (due to variations between experimental techniques, irradiation conditions, calibration procedures, etc.), and the evaluation of those experiments to extract fundamental nuclear data. A clear example of the importance of uncertainty analysis is in the justification for energy-dependent 147Nd fission product yield, where the magnitude of the effect is comparable to the uncertainties of the individual fission product yield measurements. Both LANL and LLNL are committed to the inclusion of full uncertainty analysis in their evaluations. (6) The Panel reviewed in detail two methods for determining/evaluating fission product yields from which fission assessments can be made: the K factor method and high-resolution gamma spectroscopy (both described more fully in Sections 3 and 4). The panel concluded that fission product yields, and thus fission assessments, derived using either approach are equally valid, provided that the data were obtained from well understood, direct fission measurements and that the key underlying calibrations and/or data are valid for each technique. (7) The Panel found the process of peer review of the two complementary but independent methods to be an extremely useful exercise. Although work is still ongoing and the numbers presented to the Panel may change slightly, both groups are now in much better agreement on not just one, but four key fission product yields. The groups also have a better appreciation of the strengths and weaknesses of each other's methods.
Book Synopsis The Measurement of Fallout Fission Products by Computer Analysis of the Gamma-ray Spectra by : Wilfred Sewchand
Download or read book The Measurement of Fallout Fission Products by Computer Analysis of the Gamma-ray Spectra written by Wilfred Sewchand and published by . This book was released on 1970 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Nuclear Data written by and published by . This book was released on 1957 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
