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Full-Text Articles in Engineering

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 Mar 2023

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 Jan 2023

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 …


Enabling Rapid Chemical Analysis Of Plutonium Alloys Via Machine Learning-Enhanced Atomic Spectroscopy Techniques, Ashwin P. Rao Sep 2022

Enabling Rapid Chemical Analysis Of Plutonium Alloys Via Machine Learning-Enhanced Atomic Spectroscopy Techniques, Ashwin P. Rao

Theses and Dissertations

Analytical atomic spectroscopy methods have the potential to provide solutions for rapid, high fidelity chemical analysis of plutonium alloys. Implementing these methods with advanced analytical techniques can help reduce the chemical analysis time needed for plutonium pit production, directly enabling the 80 pit-per-year by 2030 manufacturing goal outlined in the 2018 Nuclear Posture Review. Two commercial, handheld elemental analyzers were validated for potential in situ analysis of Pu. A handheld XRF device was able to detect gallium in a Pu surrogate matrix with a detection limit of 0.002 wt% and a mean error of 8%. A handheld LIBS device was …


Feasibility Of Fireball Trail Detection Using Ground-Based Gps Receivers, Ian R. Moffett Mar 2022

Feasibility Of Fireball Trail Detection Using Ground-Based Gps Receivers, Ian R. Moffett

Theses and Dissertations

The feasibility of using GPS data to detect fireballs is analyzed by first modeling the fireball’s trail diffusion and plasma chemistry to get a resulting ion density profile of the trail over time. The signal perturbation caused by the fireball trail is simulated for a ground receiver using an analytic solution for diffraction from a Gaussian lens. Five cases were modeled with varying initial peak ion densities and altitudes taken from fireball and reentry vehicle data. This paper shows that it is feasible to detect a fireball trail using GPS if the fireball has a sufficiently high initial ion density, …


Capability Development For Advanced (N,X) Nuclear Data Measurements, Brian G. Frandsen Mar 2022

Capability Development For Advanced (N,X) Nuclear Data Measurements, Brian G. Frandsen

Theses and Dissertations

Nuclear reaction data are the heart of radiation transport calculations, models, and simulations. Unique approaches are required to improve the measurement capability for many reactions where data are inaccurate or do not exist. First, the newly developed Gamma Energy Neutron Energy Spectrometer for Inelastic Scattering (GENESIS) provides the ability to measure neutron inelastic scattering cross sections on different targets. An initial experiment measuring the 16O(n,n’𝛾) reaction calculated the count rate from the second excited state using the full energy and escape peaks. Second, a set of photocurable scintillator resin formulations capable of neutron-gamma discrimination were developed to support light-based …


Deep Learning Approach To Multi-Phenomenological Nuclear Fuel Cycle Signals For Nonproliferation Applications, Preston J. Dicks Mar 2022

Deep Learning Approach To Multi-Phenomenological Nuclear Fuel Cycle Signals For Nonproliferation Applications, Preston J. Dicks

Theses and Dissertations

In order to reduce the time required for data analysis and decision-making relevant to nuclear proliferation detection, Artificial Intelligence (AI) techniques are applied to multi-phenomenological signals emitted from nuclear fuel cycle facilities to identify non-human readable characteristic signatures of operations for use in detecting proliferation activities. Seismic and magnetic emanations were collected in the vicinity of the High Flux Isotope Reactor (HFIR) and the McClellan Nuclear Research Center (MNRC). A novel bi-phenomenology DL network is designed to test the viability of transfer learning between nuclear reactor facilities. It is found that the network produces an 84.1% accuracy (99.4% without transient …


Neutron Spectral Effect On Microelectronic Performance Response, Wade Kloppenburg Mar 2022

Neutron Spectral Effect On Microelectronic Performance Response, Wade Kloppenburg

Theses and Dissertations

Response of 2N2222 bipolar junction transistors to neutrons from a pulsed thermonuclear or pulsed fission source are researched. Measurements used for comparing performance included the base-collector junction current-voltage and capacitance-voltage characteristics and device gain degradation. Little change was detected in steady-state operation of the base-collector junction, but evidence in the dynamic and capacitance measurements establish effects based on environment. Experimental results are compared to literature results and parameters are explored using a device model simulation code.


Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott Mar 2022

Analysis Of Microscopic Carbon Fiber Fragments, Zachary R. Scott

Theses and Dissertations

Carbon Fiber (CF) has different tensile strengths and transverse moduli depending on how they are fabricated. Some CF is export controlled as it can be used for weapons, spacecraft, or gas centrifuges for enriching nuclear fuel. This research project explored a new way to prepare micron sized single CF threads to measure their transverse modulus and compare the moduli of non-export controlled CF to that of an export controlled CF. Five total polyacrylonitrile (PAN) fibers were used in this project, one of which was an export controlled fiber.


Modeling Gadolinium Self Powered Neutron Detectors In A Transient Reactor, Alexander L. Q. Spring Mar 2022

Modeling Gadolinium Self Powered Neutron Detectors In A Transient Reactor, Alexander L. Q. Spring

Theses and Dissertations

Contributions to the electron current from the three components of a gadolinium SPND, emitter, insulator, and sheath, are identified, characterized, and quantified to provide information on how the SPND interacts within the transient neutron and photon flux of the TREAT to create a measurable current. These contributions are measured by defining the SPND interactions as a dose response function used within a Monte Carlo simulation of a TREAT experiment. The data obtained from the Monte Carlo simulations are then used to compare against two analytic models, developed by Jaschik and Warren, as well as the experimental results. It was found …


Optimization Of A Multi-Layered Target For A Pulsed Power Neutron Source, Zachary D. Bretz Mar 2022

Optimization Of A Multi-Layered Target For A Pulsed Power Neutron Source, Zachary D. Bretz

Theses and Dissertations

The ability to create neutron environments is critical fora wide variety of applications including national security, materials science, and medical research. It is also helpful in medical, material, and other research. The U.S. Naval Research Laboratory (NRL), Washington, DC, is interested in leveraging their pulsed-power facilities to produce an in-house, relatively inexpensive neutron source. NRL’s facilities produce 2 MeV (from Gamble II) and 5 MeV (from Mercury) protons and deuterons. This research explored combinations of target materials to produce the most neutrons in the forward direction. Models of the reactions involved were first validated against literature experiments, then target designs …


Verficiation And Validation Of Unstructured Meshing Capabilities In Mcnp6, Micah C. Jeroutek Mar 2022

Verficiation And Validation Of Unstructured Meshing Capabilities In Mcnp6, Micah C. Jeroutek

Theses and Dissertations

Discrepancies were found between the legacy CSGs and the new UMs with the latter's introduction in MCNP6. As such, V&V of UMs in MCNP must be conducted to assist in their further development and increase user confidence in them. Currently, the MCNP test suite is lacking in UM benchmarks, and of the few that are present, their range in problem type is limited. To address these issues, two preliminary test cases covering new applications of UMs were developed for future inclusion in the test suite. The first was for the Athena-I experiment which involved the study of electronic devices' responses …


Verification And Validation Of Radiation Protection Factors From Monte Carlo Simulations, William J. Erwin Sep 2021

Verification And Validation Of Radiation Protection Factors From Monte Carlo Simulations, William J. Erwin

Theses and Dissertations

This dissertation describes the verification and validation of methods for producing radiation protection factors (RPFs) using experiments and Monte Carlo N-Particle 6 (MCNP6) simulations. RPF validation of a steel enclosure using a plutonium-beryllium source produced a validated RPF with statistically significant agreement between neutron MCNP6 models and experiments and a gamma protection factor (GPF) with statistically significant agreement to the measured GPF. Efforts to validate more complex enclosures using the Fast Burst Reactor (FBR) yielded the first-ever direct measurements of this reactor’s prompt gamma emission spectrum and revealed irreconcilable differences between the FBR facility-provided source spectrum and spectrometer measurements, resulting …


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 Jul 2021

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 May 2021

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 ( …


Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik Mar 2021

Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik

Theses and Dissertations

There is a need to quickly and accurately determine the likely physical origins of a collected sample for nuclear treaty verification purposes. The objective of this research is to prove there is a means to relate different samples (Q-values) to one another using a 'same versus not-same' artificial neural network called a Siamese network. This would provide the capability of comparing an unknown sample to a database of samples with known physical origins. Using moment transformations on current data has shown to increase the prediction capabilities of a Siamese network, and using a triplet loss function in connection with the …


Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger Mar 2021

Characterization And Analysis Of Bomarc Accident Debris, Aaron J. Heffelfinger

Theses and Dissertations

Accidents involving nuclear weapons, such as the Boeing Michigan Aeronautical Research Center (BOMARC) accident in 1960, always pose a significant risk of allowing particles composed of nuclear materials to enter the environment. These particles often differ in characteristics and can be of greatly varying sizes. Gamma ray analysis was conducted on the soil sample and radioisotopes within the sample were identified. Two non-destructive methods for locating actinide bearing particles within the sample were testing, resulting in 70 actinide bearing particles ranging from 1-34 microns being identified. These 70 particles underwent both morphological and elemental characterization, indicating uranium and other elements.


Characterization Of The Spatial Distribution And Evolution Of Cerium And Calcium In Laser Produced Plasma, Michael G. Rynders Mar 2021

Characterization Of The Spatial Distribution And Evolution Of Cerium And Calcium In Laser Produced Plasma, Michael G. Rynders

Theses and Dissertations

Understanding plasma plumes and the distribution of plasma species microseconds after their formation has a variety of applications in fields such as hypersonics, explosion and combustion dynamics, and nuclear fireball chemistry. In this work, Laser Induced Breakdown Spectroscopy (LIBS) using double pulses of 532 nm light were used to analyze samples of cerium in atmospheres of air, vacuum, and argon. Cerium was used in this experiment to serve as a plutonium surrogate. CeO2 powder was pressed with CaO at 90-10 ratio to produce calcium doped pellets for use as sputtering targets. Inclusion of calcium impurities allowed the identification of …


Lithium Compound Characterization Via Laser Induced Breakdown Spectroscopy And Raman Spectroscopy, James T. Stofel Mar 2021

Lithium Compound Characterization Via Laser Induced Breakdown Spectroscopy And Raman Spectroscopy, James T. Stofel

Theses and Dissertations

Industries such as lithium-ion battery producers and the nuclear industry community seek to produce and store lithium in pure chemical forms. However, these lithium compounds are reactive with the atmosphere and quickly degrade into less desirable forms. Therefore, industry desires a fast and effective quality control approach to quantify the ingrowth of these secondary lithium chemical forms. This research presents a novel approach using Laser-Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy in tandem to enhance lithium compound characterization beyond what is achieved by either technique alone. The resulting spectral data are aggregated using data fusion and analyzed using chemometrics for …


Space To High-Altitude Region Adjoint Neutron Transport, Zachary W. Lamere Mar 2021

Space To High-Altitude Region Adjoint Neutron Transport, Zachary W. Lamere

Theses and Dissertations

The goal of this work was to use the adjoint transport equation to characterize the energy spectrum of a point neutron source using the time-energy fluence at the satellite. The adjoint transport was solved via Monte Carlo methods in the new program called Space to Air High-Altitude Region Adjoint (SAHARA). A new adjoint source event estimator was developed to improve the computational efficiency. This work explores SAHARA’s performance using mono-energetic and continuous sources. In general, the identified source spectra were noticeably shifted towards lower energies, but were able to capture the source spectrum shapes. Lastly, SAHARA was applied to the …


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 Feb 2021

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 Jan 2021

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 Jul 2020

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 May 2020

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 …


The Effect Of Aeration Rate And Free-Floating Carrier Media On The Emission Of Bacillus Globigii In Bioaerosols, Andrew J. Owens Mar 2020

The Effect Of Aeration Rate And Free-Floating Carrier Media On The Emission Of Bacillus Globigii In Bioaerosols, Andrew J. Owens

Theses and Dissertations

Aerosols produced by turbulent mechanical mixing and bubble aeration at Waste Water Treatment Plants (WWTPs) become bioaerosols with the entrainment of biological materials. Bioaerosols become a public health risk when human pathogens are present. This study evaluated bioaerosols containing Bacillus globigii (BG) spores, and the effects that aeration rate and the addition of Free-Floating Carrier Media (FFCM) had on the amount of BG spores collected following aerosolization. A series of laboratory-scale experiments investigated two different sizes of floating polystyrene spheres as FFCM and four different aeration rates. When the differences in compared aeration rates were sufficiently large, a positive correlation …


Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv Mar 2020

Neutron Energy Effects On Asteroid Deflection, Lansing S. Horan Iv

Theses and Dissertations

In the future, a hazardous asteroid will find itself on a collision course with Earth. It is an inevitability; the question is not if, but when. 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 changing the output neutron energy from a nuclear device detonation affects asteroid deflection. The notional asteroid target was 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. To calculate the …


Analysis Of The Correlation Between Re Filament Surface Features And Tims Performance, Christopher J. Mihal Mar 2020

Analysis Of The Correlation Between Re Filament Surface Features And Tims Performance, Christopher J. Mihal

Theses and Dissertations

Thermal Ionization Mass Spectrometry (TIMS) is an invaluable tool in nuclear forensics as it enables isotopic assays of actinides to be measured, permitting analysis to include special nuclear material isotopic assays, nuclear reactor monitoring, and treaty verification. In one method of measurement for the TIMS system, samples are deposited in solution form on high-purity rhenium filaments. The filaments are heated to evaporate the solvent, and then further heated to cause sample ionization, permitting the sample to be transmitted through a magnetic field which separates ions based on mass to charge ratio into detectors for counting. Heavier ions will be deflected …


Measurement Of The 160Gd(P,N)160Tb Excitation Function From 4 18 Mev, Using A Stacked Foil Technique, Ryan K. Chapman Mar 2020

Measurement Of The 160Gd(P,N)160Tb Excitation Function From 4 18 Mev, Using A Stacked Foil Technique, Ryan K. Chapman

Theses and Dissertations

A stack of thin Gd, Ti, and Cu foils were irradiated with an 18 MeV proton beam at Lawrence-Berkeley National Laboratory's 88-Inch Cyclotron to investigate the 160Gd(p,n)160Tb nuclear reaction for nuclear forensics applications. This experiment will improve knowledge of 160Tb production rates, allowing 160Tb to be efficiently created in a foil stack consisting of other proton induced isotopes for forensics applications. A set of 15 measured cross sections between 4-18 MeV for 160Gd(p,n)160Tb were obtained using a stacked foil technique. The foil stack consisted of one stainless steel, one iron, fifteen gadolinium, …


Neutron Displacement Damage In Germanium Tin Photodiodes, Nathan J. Gale Mar 2020

Neutron Displacement Damage In Germanium Tin Photodiodes, Nathan J. Gale

Theses and Dissertations

GeSn is a promising material for photodiodes in the near-to-mid infrared (IR) spectrum because of new growth methods that enable integration with complementary metal oxide semiconductor (CMOS) technology. While natural germanium has a threshold wavelength of 1800 nm, 6.9 Sn content extends the threshold wavelength to 2700 nm based on a Sn content dependent bandgap. Also, unlike other semiconductors that require liquid nitrogen cooling to act as an IR sensor, GeSn can be operated at room temperature, enabling a wide variety of applications. In this study, photodiodes ranging from 0 to 6.9 tin content were subjected to 1 MeV (Si) …


Rapid Analysis Of Plutonium Surrogate Material Via Hand-Held Laser-Induced Breakdown Spectroscopy, Ashwin P. Rao Mar 2020

Rapid Analysis Of Plutonium Surrogate Material Via Hand-Held Laser-Induced Breakdown Spectroscopy, Ashwin P. Rao

Theses and Dissertations

This work investigated the capability of a portable LIBS device to detect and quantify dopants in plutonium surrogate alloys, specifically gallium, which is a common stabilizer used in plutonium alloys. The SciAps Z500-ER was utilized to collect spectral data from cerium-gallium alloys of varying gallium concentrations. Calibration models were built to process spectra from the Ce-Ga alloys and calculate gallium concentration from spectral emission intensities. Univariate and multivariate analysis techniques were used to determine limits of detection of different emission line ratios. Spatial mapping measurements were conducted to determine the device's ability to detect variations in gallium concentration on the …


Determination And Simulation Of The Neutron Spectrum Of Nuclear Detonations And Surrogate Sources, Taylor M. Nichols Mar 2020

Determination And Simulation Of The Neutron Spectrum Of Nuclear Detonations And Surrogate Sources, Taylor M. Nichols

Theses and Dissertations

This research determined a methodology for characterizing the Fast Beam Facility (FBF) at The Ohio State University Nuclear Reactor Laboratory to test the response of photovoltaic arrays to nuclear weapon radiation. Additionally, this research developed neutron and gamma nuclear weapon output spectra of two environments for comparison to the FBF spectrum. A Bonner sphere spectrometer (BSS), coupled with the unfolding program Maximum Entropy Deconvolution (MAXED), was employed as a means of determining the energy spectrum of neutrons. Using the ISO 8529 americium beryllium (AmBe) source as the a priori default spectrum, MAXED was used to unfold the spectrum of neutrons …