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Final Report For Nuclear Resonance Fluorescence Measurements Of 239pu Above 25 Mev
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Book Synopsis Final Report for Nuclear Resonance Fluorescence Measurements of 239Pu Above 2.5 MeV. by :
Download or read book Final Report for Nuclear Resonance Fluorescence Measurements of 239Pu Above 2.5 MeV. written by and published by . This book was released on 2009 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Resonance Fluorescence measurements were performed at the free electron laser facility at UC Santa Barbara using a bremsstrahlung beam. Three endpoint energies were chosen for the bremsstrahlung to cover as much area above 2.5 MeV as possible. We were able to set an upper limit of NRF state strengths between 2.5 and 3.8 MeV at roughly 38(5) eV barns at the 4-sigma level and 9(2) eV barns at the 1-sigma level. Published results on states near 2.4 MeV indicate strengths about 10(2) eV barns. Details of the results are presented in this report.
Book Synopsis Examining 239Pu and 240Pu Nuclear Resonance Fluorescence Measurements on Spent Fuel for Nuclear Safeguards by :
Download or read book Examining 239Pu and 240Pu Nuclear Resonance Fluorescence Measurements on Spent Fuel for Nuclear Safeguards written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Resonance Fluorescence Excitations Near 2 MeV in 235U and 239Pu by :
Download or read book Nuclear Resonance Fluorescence Excitations Near 2 MeV in 235U and 239Pu written by and published by . This book was released on 2006 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for nuclear resonance fluorescence excitations in 235U and 239Pu within the energy range of 1.0- to 2.5-MeV was performed using a 4-MeV continuous bremsstrahlung source at the High Voltage Research Laboratory at the Massachusetts Institute of Technology. Measurements utilizing high purity Ge detectors at backward angles identified 9 photopeaks in 235U and 12 photopeaks in 239Pu in this energy range. These resonances provide unique signatures that allow the materials to be non-intrusively detected in a variety of environments including fuel cells, waste drums, vehicles and containers. The presence and properties of these states may prove useful in understanding the mechanisms for mixing low-lying collective dipole excitations with other states at low excitations in heavy nuclei.
Book Synopsis Measurements of Nuclear Resonance Fluorescence on the 1.27 Mev Level of Sn−p116 −s by : John M. Gonser
Download or read book Measurements of Nuclear Resonance Fluorescence on the 1.27 Mev Level of Sn−p116 −s written by John M. Gonser and published by . This book was released on 1964 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis FY08 Annual Report for Nuclear Resonance Fluorescence Imaging by :
Download or read book FY08 Annual Report for Nuclear Resonance Fluorescence Imaging written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: FY08 annual report for project the "Nuclear Resonance Fluorescence Imaging" project. Reviews accomplishments of last 3 years, including U-235 signature search, comparison of different photon sources, and examination of NRF measurements using monochromatic photon source.
Book Synopsis Nuclear Resonance Fluorescence for Nuclear Materials Assay by : Brian Joseph Quiter
Download or read book Nuclear Resonance Fluorescence for Nuclear Materials Assay written by Brian Joseph Quiter and published by . This book was released on 2010 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation examines the measurement of nuclear resonance fluorescence gamma-rays as a technique to non-destructively determine isotopic compositions of target materials that are of interest for nuclear security applications. The physical processes that can result in non-resonant background to nuclear resonance fluorescence measurements are described and investigated using a radiation transport computer code that relies on the Monte Carlo technique, MCNPX. The phenomenon of nuclear resonance fluorescence is discussed with consideration of the angular distributions of resonance emissions, the effects of nuclear recoil, and the influence of thermal motion. Models describing two ways of measuring nuclear resonance fluorescence rates in materials are considered. First the measurement of back-scattered photons is considered. In this type of measurement, the portion of the interrogating photon beam that is scattered into large relative angles is measured. When the radioactivity of the target can be overcome by shielding or by use of intense photon sources, direct measurement of gamma-rays, emitted during nuclear resonance fluorescence can provide quantitative signatures that appear to be useful for applications such as forensic age-dating of large radiological sources. However, if the target radioactivity is too intense, as in the case for most spent nuclear fuel, a second measurement type, where indirect measurement of transmitted resonant-energy photons can also provide quantitative information. This method allows radiation detectors to be better-shielded from target radioactivity, but suffers from a slower accrual rate of statistical confidence. The models described herein indicate that very intense photon sources and large high-resolution detector arrays would be needed to measure 239Pu content in spent fuel to precisions desired by nuclear safeguards organizations. However, the rates at which statistics accrue are strongly proportional to the strengths of the resonances, and measurement of a plutonium isotope with stronger resonances may provide more practical measurement rates. The model for predicting relative detection rates of nuclear resonance fluorescence gamma-rays in the transmission measurement was experimentally tested using the 238U in a mixture of depleted uranium and lead as a surrogate for 239Pu in spent fuel. The experiment indicated that the model was approximately correct, but that the process of notch refilling, which was excluded from the initial model, appears to be visible. Data files of the computer code, MCNPX, were modified to allow for nuclear resonance fluorescence to be simulated and a bug in the code was repaired to allow the code to more accurately simulate non-resonant elastic photon scattering. Simulations using this modified version of MCNPX have indicated that the magnitude of the notch refill process is comparable to that of the difference between the analytical model and the experimental data.
Book Synopsis Applications of Photonuclear Physics for International Safeguards and Security by :
Download or read book Applications of Photonuclear Physics for International Safeguards and Security written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of nuclear resonance fluorescence based applications are presented. Important for these applications are data for isotopes such as 239Pu. Nuclear resonance fluorescence measurements of 239Pu were performed at the free electron laser facility at UC Santa Barbara using photons from a bremsstrahlung beam with an endpoint energies between 4.0 MeV and 5.5 MeV. Though no discrete states with significant confidence level were measured, we have excluded the region above 27(3) eV-barns, or 4-sigma, where we would expect only a small chance of false positives. Details of the measurements and the results are presented here.
Book Synopsis Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay by :
Download or read book Assessment of Nuclear Resonance Fluorescence for Spent Nuclear Fuel Assay written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of gamma rays with specific energies that are characteristic of the emitting isotope. NRF promises the unique capability of directly quantifying a specific isotope without the need for unfolding the combined responses of several fissile isotopes as is required in other measurement techniques. We have analyzed the potential of NRF as a non-destructive analysis technique for quantitative measurements of Pu isotopes in spent nuclear fuel (SNF). Given the low concentrations of 239Pu in SNF and its small integrated NRF cross sections, the main challenge in achieving precise and accurate measurements lies in accruing sufficient counting statistics in a reasonable measurement time. Using analytical modeling, and simulations with the radiation transport code MCNPX that has been experimentally tested recently, the backscatter and transmission methods were quantitatively studied for differing photon sources and radiation detector types. Resonant photon count rates and measurement times were estimated for a range of photon source and detection parameters, which were used to determine photon source and gamma-ray detector requirements. The results indicate that systems based on a bremsstrahlung source and present detector technology are not practical for high-precision measurements of 239Pu in SNF. Measurements that achieve the desired uncertainties within hour-long measurements will either require stronger resonances, which may be expressed by other Pu isotopes, or require quasi-monoenergetic photon sources with intensities that are approximately two orders of magnitude higher than those currently being designed or proposed. This work is part of a larger effort sponsored by the Next Generation Safeguards Initiative to develop an integrated instrument, comprised of individual NDA techniques with complementary features, that is fully capable of determining Pu mass in spent fuel assemblies.
Book Synopsis Nuclear Resonance Fluorescence for Safeguards Applications by :
Download or read book Nuclear Resonance Fluorescence for Safeguards Applications written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In nuclear resonance fluorescence (NRF) measurements, resonances are excited by an external photon beam leading to the emission of [gamma] rays with specific energies that are characteristic of the emitting isotope. The promise of NRF as a non-destructive analysis technique (NDA) in safeguards applications lies in its potential to directly quantify a specific isotope in an assay target without the need for unfolding the combined responses of several fissile isotopes as often required by other NDA methods. The use of NRF for detection of sensitive nuclear materials and other contraband has been researched in the past. In the safeguards applications considered here one has to go beyond mere detection and precisely quantify the isotopic content, a challenge that is discussed throughout this report. Basic NRF measurement methods, instrumentation, and the analytical calculation of NRF signal strengths are described in Section 2. Well understood modeling and simulation tools are needed for assessing the potential of NRF for safeguards and for designing measurement systems. All our simulations were performed with the radiation transport code MCNPX, a code that is widely used in the safeguards community. Our initial studies showed that MCNPX grossly underestimated the elastically scattered background at backwards angles due to an incorrect treatment of Rayleigh scattering. While new, corrected calculations based on ENDF form factors showed much better agreement with experimental data for the elastic scattering of photons on an uranium target, the elastic backscatter is still not rigorously treated. Photonuclear scattering processes (nuclear Thomson, Delbruck and Giant Dipole Resonance scattering), which are expected to play an important role at higher energies, are not yet included. These missing elastic scattering contributions were studied and their importance evaluated evaluated against data found in the literature as discussed in Section 3. A transmission experiment was performed in September 2009 to test and demonstrate the applicability of the method to the quantitative measurement of an isotope of interest embedded in a thick target. The experiment, data analysis, and results are described in Section 4. The broad goal of our NRF studies is to assess the potential of the technique in safeguards applications. Three examples are analyzed in Section 5: the isotopic assay of spent nuclear fuel (SNF), the measurement of 235U enrichment in UF6 cylinders, and the determination of 239Pu in mixed oxide (MOX) fuel. The study of NRF for the assay of SNF assemblies was supported by the Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy as part of a large multi-lab/university effort to quantify the plutonium (Pu) mass in spent nuclear fuel assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. NRF is one of 14 NDA techniques being researched. The methodology for performing and analyzing quantitative NRF measurements was developed for determining Pu mass in SNF and is extensively discussed in this report. The same methodology was applied to the assessment of NRF for the measurement of 235U enrichment and the determination of 239Pu in MOX fuel. The analysis centers on determining suitable NRF measurement methods, measurement capabilities that could be realized with currently available instrumentation, and photon source and detector requirements for achieving useful NDA capabilities.
Book Synopsis Nuclear Resonance Fluorescence Experiments on _1hn2_1hn0_1hn4_1hn,_1hn2_1hn0_1hn6_1hn,_1hn2_1hn0_1hn7_1hn_,_1hn2_1hn0_1hn8Pb Up to 6.75 MeV by :
Download or read book Nuclear Resonance Fluorescence Experiments on _1hn2_1hn0_1hn4_1hn,_1hn2_1hn0_1hn6_1hn,_1hn2_1hn0_1hn7_1hn_,_1hn2_1hn0_1hn8Pb Up to 6.75 MeV written by and published by . This book was released on 2003 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Repetition Rate, LINAC-Based Nuclear Resonance Fluorescence FY 2008 Final Report by :
Download or read book High Repetition Rate, LINAC-Based Nuclear Resonance Fluorescence FY 2008 Final Report written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This summarizes the first year of a multi-laboratory/university, multi-year effort focusing on high repetition rate, pulsed LINAC-based nuclear resonance fluorescence (NRF) measurements. Specifically, this FY2008 effort centered on experimentally assessing NRF measurements using pulsed linear electron accelerators, operated at various repetition rates, and identifying specific detection requirements to optimize such measurements. Traditionally, interest in NRF as a detection technology, which continues to receive funding from DHS and DOE/NA-22, has been driven by continuous-wave (CW), Van de Graff-based bremsstrahlung sources. However, in addition to the relatively sparse present-day use of Van de Graff sources, only limited NRF data from special nuclear materials has been presented; there is even less data available regarding shielding effects and photon source optimization for NRF measurements on selected nuclear materials.
Book Synopsis Nuclear Resonance Fluorescence Measurements on 237Np for Security and Safeguards Applications by : Ryan Matthew Yee
Download or read book Nuclear Resonance Fluorescence Measurements on 237Np for Security and Safeguards Applications written by Ryan Matthew Yee and published by . This book was released on 2009 with total page 102 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 1976-03 with total page 938 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Level Parameters from Resonance Fluorescence at 7 Mev by : Kurt Reibel
Download or read book Nuclear Level Parameters from Resonance Fluorescence at 7 Mev written by Kurt Reibel and published by . This book was released on 1960 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Repetition Rate, LINAC-based Nuclear Resonance Fluorescence FY 2009 Final Report by :
Download or read book High Repetition Rate, LINAC-based Nuclear Resonance Fluorescence FY 2009 Final Report written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Resonance Fluorescence (NRF), which is possible for nuclei with atomic numbers greater than helium (Z=2), occurs when a nuclear level is excited by resonant absorption of a photon and subsequently decays by reemission of a photon. The excited nuclear states can become readily populated, provided the incident photon's energy is within the Doppler-broadened width of the energy level being excited. Utilizing continuous energy photon spectra, as is characteristic of a bremsstrahlung photon beam, as the inspection source, ensures that at least some fraction of the impinging beam will contribute to the population of the excited energy levels in the material of interest. Upon de-excitation, either to the ground state or to a lower-energy excited state, the emitted fluorescence photon's energy will correspond to the energy difference between the excited state and the state to which it decays. As each isotope inherently contains unique nuclear energy levels, the NRF states for each isotope are also unique. By exploiting this phenomenon, NRF photon detection provides a well-defined signature for identifying the presence of individual nuclear species. This report summarizes the second year (Fiscal Year [FY] 2009) of a collaborative research effort between Idaho National Laboratory, Idaho State University's Idaho Accelerator Center, and Pacific Northwest National Laboratory. This effort focused on continuing to assess and optimize NRF-based detection techniques utilizing a slightly modified, commercially available, pulsed medical electron accelerator.
Book Synopsis Nuclear Resonance Fluorescence Experiments on 204, 206, 207, 208 Pb Up to 6.75 MeV by : Joachim Enders
Download or read book Nuclear Resonance Fluorescence Experiments on 204, 206, 207, 208 Pb Up to 6.75 MeV written by Joachim Enders and published by . This book was released on 2003 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel by :
Download or read book Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, 252Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size, development time, nor concerns related to the use of Pu in measurement systems. This report discusses basic NRF measurement concepts, i.e., backscatter and transmission methods, and photon source and [gamma]-ray detector options in Section 2. An analytical model for calculating NRF signal strengths is presented in Section 3 together with enhancements to the MCNPX code and descriptions of modeling techniques that were drawn upon in the following sections. Making extensive use of the model and MCNPX simulations, the capabilities of the backscatter and transmission methods based on bremsstrahlung or quasi-monoenergetic photon sources were analyzed as described in Sections 4 and 5. A recent transmission experiment is reported on in Appendix A. While this experiment was not directly part of this project, its results provide an important reference point for our analytical estimates and MCNPX simulations. Used fuel radioactivity calculations, the enhancements to the MCNPX code, and details of the MCNPX simulations are documented in the other appendices.
