Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Machine learning (2)
- Nuclear forensics (2)
- #antcenter (1)
- 3D printing (1)
- Activation foils (1)
-
- Additive manufacturing (1)
- Analytical chemistry (1)
- Analytical techniques (1)
- Artificial neural networks (1)
- Asteroid deflection (1)
- Asteroid planetary defense (1)
- Blow-off momentum impulse (1)
- CANDU (1)
- CBRN (1)
- Carbon/silicon segregation (1)
- Chemical analysis (1)
- Combat Operations (1)
- Curriculum (1)
- DFT optimization (1)
- Density function theory (1)
- Detector instrumentation (1)
- Detector response (1)
- Energy coupling efficiency (1)
- Energy deposition profile (1)
- Energy depositions (1)
- FA 52 (1)
- GEB (1)
- Gamma Spectrum (1)
- Gamma rays (1)
- Gamma-ray detection (1)
- Publication
Articles 1 - 20 of 20
Full-Text Articles in Engineering
Measuring Radiation Protection: Partners From Across The Nuclear Enterprise Evaluate The Radiation Protection Of Us Army Vehicles, Andrew W. Decker, Robert Prins
Measuring Radiation Protection: Partners From Across The Nuclear Enterprise Evaluate The Radiation Protection Of Us Army Vehicles, Andrew W. Decker, Robert Prins
Faculty Publications
Recent mounting nuclear threats and postures from adversary nation-states, such as Russia, China, North Korea, and Iran, represent a clear danger to the interests and security of the United States of America and its Allies. To meet these threats, the 2022 Nuclear Posture Review requires the Department of Defense (DoD) to design, develop, and manage a combat-credible U.S. military which, among other prioritizations, is survivable. A survivable force can generate combat power despite adversary attacks. As such, the US Army must prepare today to set the conditions for successful conventional warfare on the nuclear battlefields of tomorrow. Our Army cannot …
Fast-, Light-Cured Scintillating Plastic For 3d-Printing Applications, Brian G. Frandsen, Michael Febbraro, Thomas Ruland, Theodore W. Stephens, Paul A. Hausladen, Juan J. Manfredi, James E. Bevins
Fast-, Light-Cured Scintillating Plastic For 3d-Printing Applications, Brian G. Frandsen, Michael Febbraro, Thomas Ruland, Theodore W. Stephens, Paul A. Hausladen, Juan J. Manfredi, James E. Bevins
Faculty Publications
Additive manufacturing techniques enable a wide range of possibilities for novel radiation detectors spanning simple to highly complex geometries, multi-material composites, and metamaterials that are either impossible or cost prohibitive to produce using conventional methods. The present work identifies a set of promising formulations of photocurable scintillator resins capable of neutron-gamma pulse shape discrimination (PSD) to support the additive manufacturing of fast neutron detectors. The development of these resins utilizes a step-by-step, trial-and-error approach to identify different monomer and cross-linker combinations that meet the requirements for 3D printing followed by a 2-level factorial parameter study to optimize the radiation detection …
Data Augmentation For Neutron Spectrum Unfolding With Neural Networks, James Mcgreivy, Juan J. Manfredi, Daniel Siefman
Data Augmentation For Neutron Spectrum Unfolding With Neural Networks, James Mcgreivy, Juan J. Manfredi, Daniel Siefman
Faculty Publications
Neural networks require a large quantity of training spectra and detector responses in order to learn to solve the inverse problem of neutron spectrum unfolding. In addition, due to the under-determined nature of unfolding, non-physical spectra which would not be encountered in usage should not be included in the training set. While physically realistic training spectra are commonly determined experimentally or generated through Monte Carlo simulation, this can become prohibitively expensive when considering the quantity of spectra needed to effectively train an unfolding network. In this paper, we present three algorithms for the generation of large quantities of realistic and …
Aerial Radiation Detection Identification And Measurement System Detector Material Comparison Study, Benjamin C. Troxell, Kacey D. Mcgee, Christina L. Dugan
Aerial Radiation Detection Identification And Measurement System Detector Material Comparison Study, Benjamin C. Troxell, Kacey D. Mcgee, Christina L. Dugan
Faculty Publications
The 20th Chemical Biological Radiological Nuclear and Explosives Command (CBRNE) currently utilizes an airborne sodium iodide gamma and beta detection system to map radiation fields over large areas of interest. The 20th CBRNE explored emergent detector technologies utilizing two detection materials; thallium-activated cesium iodide and high purity germanium (HPGe). These detectors were simulated at various altitudes and compared to background measurements. The sodium iodide detector failed to provide isotopic discrimination at distance. The thallium-activated cesium iodide CsI(Tl) detector provided sufficient absolute efficiency and energy resolution to identify isotopics at distance. The HPGe detector provided the best energy resolution. However, current …
Uranium Integral Fission Product Yields For A Spectrally-Shaped 14.1 Mev Neutron Source At The National Ignition Facility, Nicholas J. Quartemont, N. Gharibyan, K. Moody, James E. Bevins
Uranium Integral Fission Product Yields For A Spectrally-Shaped 14.1 Mev Neutron Source At The National Ignition Facility, Nicholas J. Quartemont, N. Gharibyan, K. Moody, James E. Bevins
Faculty Publications
This paper describes the experimental results for an energy tuning assembly created to modify the National Ignition Facility deuterium–tritium fusion neutron source into a notional thermonuclear and prompt fission neutron spectrum, which has applications in integral measurements, nuclear data benchmarks, and radiation effects on microelectronics. The Monte Carlo neutron transport utilized MCNP5 to estimate the ETA-modified fluence using the ENDF-B/VIII.0 and IRDFF-II continuous energy nuclear data libraries, and SCALE Sampler was used to estimate the systematic nuclear data covariance using ENDF-B/VII.1 and IRDFF-II in a 252-group structure. The experiment fielded eight activation foils and a highly enriched uranium sample. This …
Acquiring And Modeling Of Si Solar Cell Transient Response To Pulsed X-Ray, Lei Pan, Praneeth Kandlakunta, Matthew Van Zile, Xuezeng Dai, Jinsong Huang, John W. Mcclory, Lei R. Cao
Acquiring And Modeling Of Si Solar Cell Transient Response To Pulsed X-Ray, Lei Pan, Praneeth Kandlakunta, Matthew Van Zile, Xuezeng Dai, Jinsong Huang, John W. Mcclory, Lei R. Cao
Faculty Publications
We report on the acquisition and modeling of the transient response of a commercial silicon (Si) solar cell using a benchtop pulsed X-ray source. The solar-cell transient output to the X-ray pulses was acquired under the dark and steady-state light illumination to mimic the practical operation of a solar cell under different light illumination levels. A solar-cell circuit model was created to develop a fundamental understanding of the transient current/voltage response of solar cell at read-out circuit level. The model was validated by a good agreement between the simulation and experimental results. It was found that the solar-cell resistance ( …
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt, James E. Bevins, Stephen H. Baxter
Faculty Publications
A 3-D Quarter-Core CANDU-6 is modeled using Serpent 2 for nuclear treaty monitoring. The spatial variation of flux spectra and isotopic concentrations is analyzed to determine the potential isotopic distribution of key radionuclides from standard reactor operations relevant to non-proliferation. The initial results of the model show a 46% difference in overall flux magnitude throughout the core as well as a 2-30% difference in discrete energy flux. The coupled production rate (magnitude) and spectral differences can contribute to significant spatial variations in isotope ratios throughout the core. Initial results indicate 239 Pu/ 240 Pu ratios vary by as much as …
Impact Of Neutron Energy On Asteroid Deflection Performance, Lansing S. Horan Iv, Darren E. Holland, Megan Bruck Syal, James E. Bevins, Joseph W. Wasem
Impact Of Neutron Energy On Asteroid Deflection Performance, Lansing S. Horan Iv, Darren E. Holland, Megan Bruck Syal, James E. Bevins, Joseph W. Wasem
Faculty Publications
In the future, a hazardous asteroid will find itself on a collision course with Earth. For asteroids of moderate size or larger, a nuclear device is one of humanity's only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how the output neutron energy from a nuclear device standoff detonation affects the deflection of a notional asteroid that is 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. 14.1 MeV and 1 MeV neutron energy sources were modeled in MCNP to …
Applications Of Portable Libs For Actinide Analysis, Ashwin P. Rao, John D. Auxier Ii, Dung Vu, Michael B. Shattan
Applications Of Portable Libs For Actinide Analysis, Ashwin P. Rao, John D. Auxier Ii, Dung Vu, Michael B. Shattan
Faculty Publications
A portable LIBS device was used for rapid elemental impurity analysis of plutonium alloys. This device demonstrates the potential for fast, accurate in-situ chemical analysis and could significantly reduce the fabrication time of plutonium alloys.
A Physics-Based Machine Learning Study Of The Behavior Of Interstitial Helium In Single Crystal W–Mo Binary Alloys, Adib J. Samin
A Physics-Based Machine Learning Study Of The Behavior Of Interstitial Helium In Single Crystal W–Mo Binary Alloys, Adib J. Samin
Faculty Publications
In this work, the behavior of dilute interstitial helium in W–Mo binary alloys was explored through the application of a first principles-informed neural network (NN) in order to study the early stages of helium-induced damage and inform the design of next generation materials for fusion reactors. The neural network (NN) was trained using a database of 120 density functional theory (DFT) calculations on the alloy. The DFT database of computed solution energies showed a linear dependence on the composition of the first nearest neighbor metallic shell. This NN was then employed in a kinetic Monte Carlo simulation, which took into …
Nuclear Data Covariance Analysis In Radiation-Transport Simulations Utilizing Scale Sampler And The Irdff Nuclear Data Library, Nicholas J. Quartemont, Abigail A. Bickley, James E. Bevins
Nuclear Data Covariance Analysis In Radiation-Transport Simulations Utilizing Scale Sampler And The Irdff Nuclear Data Library, Nicholas J. Quartemont, Abigail A. Bickley, James E. Bevins
Faculty Publications
This article describes the nuclear data covariance analysis of an experimental design for a neutron energy-tuning assembly (ETA) created to shape a 14-MeV neutron point source to an objective spectrum. Underlying nuclear data uncertainties play a large role in the radiation transport and reaction rates for the range of responses to be expected from an experiment. The methodology leveraged the Standardized Computer Analysis for Licensing Evaluation (SCALE) Sampler module to determine the uncertainty in the neutron transport. The reaction uncertainty was perturbed with the International Reactor Dosimetry and Fusion File v.1.05 uncertainty, correlation matrix, and reaction cross section through multivariate …
Monte Carlo And Experimental Analysis Of A Novel Directional Rotating Scatter Mask Gamma Detection System, Julie V. Logan, Darren E. Holland, Larry W. Burggraf, Justin A. Clinton, Buckley E. O'Day Iii
Monte Carlo And Experimental Analysis Of A Novel Directional Rotating Scatter Mask Gamma Detection System, Julie V. Logan, Darren E. Holland, Larry W. Burggraf, Justin A. Clinton, Buckley E. O'Day Iii
Faculty Publications
Excerpt: This work demonstrates successful experimental operation of a prototype system to identify source direction which was modeled using a library of signals simulated using GEANT and a novel algorithm....
Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders
Possible Detection Of Low Energy Solar Neutrons Using Boron Based Materials, Nicole Benker, Elena Echeverria, Robert Olesen, Brant E. Kananen, John W. Mcclory, Yaroslav V. Burak, Volodymyr T. Adamiv, Ihor M. Teslyuk, George Glenn Peterson, Ben Bradley, Ethiyal R. Wilson, James C. Petrosky, Bin Dong, Jeffry Kelber, Jennifer Hamblin, Jaques Doumani, Peter A. Dowben, Alex Enders
Faculty Publications
Solar neutrons have been detected aboard the International Space Station (ISS), using lithium tetraborate and boron carbide detector elements. We find that evidence of a solar neutron flux, as detected in a neutron calorimeter following subtraction of the proton background, with an energy of about 2 to 4 MeV. This solar neutron flux is likely no more than 250 to 375 neutrons cm−2sec−1, with a lower bound of 50–75 neutrons cm−2sec−1 at one au.
Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan
Quantitative Analysis Of Cerium-Gallium Alloys Using A Hand-Held Laser Induced Breakdown Spectroscopy Device, Ashwin P. Rao, Matthew Cook, Howard L. Hall, Michael B. Shattan
Faculty Publications
A hand-held laser-induced breakdown spectroscopy device was used to acquire spectral emission data from laser-induced plasmas created on the surface of cerium-gallium alloy samples with Ga concentrations ranging from 0–3 weight percent. Ionic and neutral emission lines of the two constituent elements were then extracted and used to generate calibration curves relating the emission line intensity ratios to the gallium concentration of the alloy. The Ga I 287.4-nm emission line was determined to be superior for the purposes of Ga detection and concentration determination. A limit of detection below 0.25%was achieved using a multivariate regression model of the Ga I …
Nuclear Engineering At The Air Force Institute Of Technology: A Unique Graduate School Experience For A Unique Set Of Students, Michael B. Shattan
Nuclear Engineering At The Air Force Institute Of Technology: A Unique Graduate School Experience For A Unique Set Of Students, Michael B. Shattan
Faculty Publications
In August 2018, the Air University Commander formed a task force to review the Air Force’s Science, Technology, Engineering, and Mathematics (STEM) graduate education programs that are delivered and administered through the Air Force Institute of Technology (AFIT). The study was rooted in strategies to support the 2018 National Defense Strategy, and provided the necessary technologically equipped personnel for the 21st century. The study was commonly referred to as “reimagining AFIT”. Several themes emerged from the study, which include reaching a broader community of Airmen through alternate educational modes (e.g. distance learning, short course etc.), forming strategic educational and research …
Evaluation Of Eu:Licaf For Neutron Detection Utilizing Sipms And Portable Electronics, Michael A. Ford, Buckley E. O'Day Iii, John W. Mcclory, Manish K. Sharma, Areg Danagoulian
Evaluation Of Eu:Licaf For Neutron Detection Utilizing Sipms And Portable Electronics, Michael A. Ford, Buckley E. O'Day Iii, John W. Mcclory, Manish K. Sharma, Areg Danagoulian
Faculty Publications
With the increasing cost and decreasing availability of 3He, there have been many efforts to find alternative neutron detection materials. Lithium calcium aluminum fluoride (LiCAF) enriched to 95% 6Li doped with europium was evaluated here as a replacement material for 3He. Wafers 0.5 cm thick, consisting of LiCAF crystals in a rubberized matrix, were embedded with wavelength shifting fibers (WSF) and mated to silicon photo-multipliers (SiPMs) to measure the photon response in a flux of neutrons from a DD neutron generator. Excellent discrimination was realized between neutrons and gammas, and both pulse-height discrimination and pulse-shape analysis were …
Developments In Capture- Γ Libraries For Nonproliferation Applications, A. M. Hurst, R. B. Firestone, B. W. Sleaford, D. L. Bleuel, M. S. Basunia, F. Becvar, T. Belgya, L. A. Bernstein, J. J. Carroll, B. Detwiler, J. E. Escher, C. Genreith, B. L. Goldblum, M. Krticka, A. G. Lerch, David A. Matters, John W. Mcclory, Stephen R. Mchale, Zs. Revay, L. Szentmiklosi, D. Turkoglu, A. Ureche, J. Vulic
Developments In Capture- Γ Libraries For Nonproliferation Applications, A. M. Hurst, R. B. Firestone, B. W. Sleaford, D. L. Bleuel, M. S. Basunia, F. Becvar, T. Belgya, L. A. Bernstein, J. J. Carroll, B. Detwiler, J. E. Escher, C. Genreith, B. L. Goldblum, M. Krticka, A. G. Lerch, David A. Matters, John W. Mcclory, Stephen R. Mchale, Zs. Revay, L. Szentmiklosi, D. Turkoglu, A. Ureche, J. Vulic
Faculty Publications
The neutron-capture reaction is fundamental for identifying and analyzing the γ-ray spectrum from an unknown assembly because it provides unambiguous information on the neutron-absorbing isotopes. Nondestructive-assay applications may exploit this phenomenon passively, for example, in the presence of spontaneous-fission neutrons, or actively where an external neutron source is used as a probe. There are known gaps in the Evaluated Nuclear Data File libraries corresponding to neutron-capture γ-ray data that otherwise limit transport-modeling applications. In this work, we describe how new thermal neutron-capture data are being used to improve information in the neutron-data libraries for isotopes relevant to nonproliferation applications. We …
Reconfigurable Liquid Attenuated Collimator, Larry W. Burggraf, Benjamin R. Kowash, Jack G. M. Fitzgerald
Reconfigurable Liquid Attenuated Collimator, Larry W. Burggraf, Benjamin R. Kowash, Jack G. M. Fitzgerald
AFIT Patents
A reconfigurable radiographic aperture mask collimator apparatus includes a body portion configured to receive an attenuating liquid having a first attenuation value per unit volume. The apparatus further includes a grid portion mated to a face of the body portion and a plurality of passageways each having a cross sectional area and a length. The plurality of passageways is disposed within the grid portion. A plurality of plugs is slidably disposed within the plurality of passageways, and each of the plurality of plugs has a second attenuation value per unit volume less than the first attenuation value. One of the …
Investigation Of 186Re Via Radiative Thermal-Neutron Capture On 185Re, David A. Matters [*], Andrew G. Lerch, A. M. Hurst, L. Szentmiklosi, J. J. Carroll, B. Detwiler, Zs. Revay, John W. Mcclory, Stephen R. Mchale, R. B. Firestone, B. W. Sleaford, M. Krticka, T. Belgya
Investigation Of 186Re Via Radiative Thermal-Neutron Capture On 185Re, David A. Matters [*], Andrew G. Lerch, A. M. Hurst, L. Szentmiklosi, J. J. Carroll, B. Detwiler, Zs. Revay, John W. Mcclory, Stephen R. Mchale, R. B. Firestone, B. W. Sleaford, M. Krticka, T. Belgya
Faculty Publications
Partial 𝛾-ray production cross sections and the total radiative thermal-neutron capture cross section for the 185Re(n,𝛾)186Re reaction were measured using the Prompt Gamma Activation Analysis facility at the Budapest Research Reactor with an enriched 185Re target. The 186Re cross sections were standardized using well-known 35Cl(n,𝛾)36Cl cross sections from irradiation of a stoichiometric natReCl3 target. The resulting cross sections for transitions feeding the 186Re ground state from low-lying levels below a cutoff energy of Ec=746keV were combined with a modeled probability of ground-state feeding from levels above E …
Searching For Stable SiNCN Clusters: Combination Of Stochastic Potential Surface Search And Pseudopotential Plane-Wave Car-Parinello Simulated Annealing Simulations, Xiaofeng F. Duan, Lingyu Huang, Larry W. Burggraf
Searching For Stable SiNCN Clusters: Combination Of Stochastic Potential Surface Search And Pseudopotential Plane-Wave Car-Parinello Simulated Annealing Simulations, Xiaofeng F. Duan, Lingyu Huang, Larry W. Burggraf
Faculty Publications
To find low energy SinCn structures out of hundreds to thousands of isomers we have developed a general method to search for stable isomeric structures that combines Stochastic Potential Surface Search and Pseudopotential Plane-Wave Density Functional Theory Car-Parinello Molecular Dynamics simulated annealing (PSPW-CPMD-SA). We enhanced the Sunders stochastic search method to generate random cluster structures used as seed structures for PSPW-CPMD-SA simulations. This method ensures that each SA simulation samples a different potential surface region to find the regional minimum structure. By iterations of this automated, parallel process on a high performance computer we located hundreds to …