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Nuclear Resonance Fluorescence For Materials Assay
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Book Synopsis Nuclear Resonance Fluorescence for Materials Assay by :
Download or read book Nuclear Resonance Fluorescence for Materials Assay written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the use of nuclear resonance fluorescence (NRF) techniques for the isotopic and quantitative assaying of radioactive material. Potential applications include age-dating of an unknown radioactive source, pre- and post-detonation nuclear forensics, and safeguards for nuclear fuel cycles Examples of age-dating a strong radioactive source and assaying a spent fuel pin are discussed. The modeling work has ben performed with the Monte Carlo radiation transport computer code MCNPX, and the capability to simulate NRF has bee added to the code. Discussed are the limitations in MCNPX?s photon transport physics for accurately describing photon scattering processes that are important contributions to the background and impact the applicability of the NRF assay technique.
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 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 Using Nuclear Resonance Fluorescence to Probe Nuclear Materials by :
Download or read book Using Nuclear Resonance Fluorescence to Probe Nuclear Materials written by and published by . This book was released on 2010 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Isotope-Specific Detection and Assay by : Vladimir Alexandrovich Semenov
Download or read book Isotope-Specific Detection and Assay written by Vladimir Alexandrovich Semenov and published by . This book was released on 2014 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work we endeavor to engineer a new tool for isotope-specific assay and detection. We propose to utilize Nuclear Resonance Fluorescence (NRF) as the process that gives isotope-specific information about the object under investigation. Careful experimental and theoretical studies of angular dependencies of signal (NRF) and noise (other significant scattering channels) are presented. These studies motivate engineering design of detector array exploiting signal vs. noise discrepancies in angular distributions. User-defined materials of interest, detection / assay times and accuracy requirements inform the design yielding optimal performance.
Book Synopsis Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis by :
Download or read book Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear resonance fluorescence (NRF) has been studied as one of the nondestructive analysis (NDA) techniques currently being investigated by a multi-laboratory collaboration for the determination of Pu mass in spent fuel. In NRF measurements specific isotopes are identified by their characteristic lines in recorded gamma spectra. The concentration of an isotope in a material can be determined from measured NRF signal intensities if NRF cross sections and assay geometries are known. The potential of NRF to quantify isotopic content and Pu mass in spent fuel has been studied. The addition of NRF data to MCNPX and an improved treatment of the elastic photon scattering at backward angles has enabled us to more accurately simulate NRF measurements on spent fuel assemblies. Using assembly models from the spent fuel assembly library generated at LANL, NRF measurements are simulated to find the best measurement configurations, and to determine measurement sensitivities and times, and photon source and gamma detector requirements. A first proof-of-principal measurement on a mock-up assembly with a bremsstrahlung photon source demonstrated isotopic sensitivity to approximately 1% limited by counting statistics. Data collection rates are likely a limiting factor of NRF-based measurements of fuel assemblies but new technological advances may lead to drastic improvements.
Book Synopsis Nuclear Physics And Gamma-ray Sources For Nuclear Security And Nonproliferation - Proceedings Of The International Symposium by : Takehito Hayakawa
Download or read book Nuclear Physics And Gamma-ray Sources For Nuclear Security And Nonproliferation - Proceedings Of The International Symposium written by Takehito Hayakawa and published by World Scientific. This book was released on 2014-10-24 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear nonproliferation is a critical global issue. A key technological challenge to ensuring nuclear nonproliferation and security is the detection of long-lived radioisotopes and fissionable nuclides in a non-destructive manner. This technological challenge requires new methods for detecting relevant nuclides and the development of new quantum-beam sources. For example, one new method that has been proposed and studied is nuclear resonance fluorescence with energy-tunable, monochromatic gamma-rays generated by Compton scattering of laser photons with electrons.The development of new methods requires the help of researchers from a wide range of fields, such as nuclear physics, accelerator physics, laser physics, etc. Furthermore, any new method must be compatible with the requirements of administrators and nuclear-material inspectors.
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 Nuclear Resonance Fluorescence in 240Pu by :
Download or read book Nuclear Resonance Fluorescence in 240Pu 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 in 27Al by : Michael J. Parrott
Download or read book Nuclear Resonance Fluorescence in 27Al written by Michael J. Parrott and published by . This book was released on 1977 with total page 226 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 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 in 31P and 55Mn by : Ronald J. Foust
Download or read book Nuclear Resonance Fluorescence in 31P and 55Mn written by Ronald J. Foust and published by . This book was released on 1969 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Resonance Fluorescence in 55Mn by : Dennis A. Justice
Download or read book Nuclear Resonance Fluorescence in 55Mn written by Dennis A. Justice and published by . This book was released on 1974 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Potential National Security Applications of Nuclear Resonance Fluorescence Methods by :
Download or read book Potential National Security Applications of Nuclear Resonance Fluorescence Methods written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this report is to document the initial investigation into the possible research issues related to the development of NRF-based national security applications. The report discusses several potential applications ranging from measuring uranium enrichment in UF6 canisters to characterization of gas samples. While these applications are varied, there are only a few research issues that need to be addressed to understand the limitation of NRF in solving these problems. These research issues range from source and detector development to measuring small samples. The next effort is to determine how best to answer the research issues, followed by a prioritization of those questions to ensure that the most important are addressed. These issues will be addressed through either analytical calculations, computer simulations, analysis of previous data or collection of new measurements. It will also be beneficial to conduct a thorough examination of a couple of the more promising applications in order to develop concrete examples of how NRF may be applied in specific situations. The goals are to develop an understanding of whether the application of NRF is limited by technology or physics in addressing national security applications, to gain a motivation to explore those possible applications, and to develop a research roadmap so that those possibilities may be made reality.
Book Synopsis Nuclear Resonance Fluorescence in Copper 65 by : John Poné
Download or read book Nuclear Resonance Fluorescence in Copper 65 written by John Poné and published by . This book was released on 1969 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nuclear Resonance Fluorescence with Bremsstrahlung by : Raymond George Arnold
Download or read book Nuclear Resonance Fluorescence with Bremsstrahlung written by Raymond George Arnold and published by . This book was released on 1972 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
