Graphene Field Effect Transistor For Radiation Detection On A Micron To Millimeter Scale,
2015
Purdue University
Graphene Field Effect Transistor For Radiation Detection On A Micron To Millimeter Scale, Peter C. Lamm, Robert Speer Bean, Zachary Shollar
The Summer Undergraduate Research Fellowship (SURF) Symposium
Novel technology in radiation detection is critical to advancing radiation detectors for their many applications. Graphene has shown to be able to change its conductivity in the presence of an electric field; this makes it an excellent candidate to be used as a radiation detector for the detection of the charges generated during radiation interactions. Research has been done on making micron scale graphene field effect transistors (GFET) with graphene on a Si/SiO2 wafer, but it is critical that we try to increase the scale. Unknowns persist in scaling graphene to millimeter sizes. This study plans to elucidate any …
Quantum Modeling Of Thermodynamic Properties Of Warm Dense Aluminum,
2015
Purdue University
Quantum Modeling Of Thermodynamic Properties Of Warm Dense Aluminum, Nicholas Termini, Gennady Miloshesky, Ahmed Hassanein
The Summer Undergraduate Research Fellowship (SURF) Symposium
Warm dense matter is attracting a lot of attention in the scientific community, due to its formation during intense laser-matter interaction and inertial confinement fusion. However, there is no accurate solution to mapping out the thermodynamic properties of warm dense matter. Experimental data are also incredibly scarce making computational models an incredibly useful tool. This paper provides equation of state (EOS) data for aluminum at specific densities within the warm dense matter regime. The EOS data were calculated using quantum molecular dynamics, which was performed by the computational package QuatumEspresso. EOS were determined by collecting and recording pressure after achieving …
Temperature Dependence Of Electrical Performance Of Tritium Sourced Betavoltaic Cells,
2015
Purdue University
Temperature Dependence Of Electrical Performance Of Tritium Sourced Betavoltaic Cells, Darrell S. Cheu, Tom Adams, Shripad Revankar
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is an increasing need for devices that can be powered for extended periods of time where it is impossible for maintenance or replacement, such as pacemakers, long term space flight or undisturbed sensors for military use. Since 1971, most devices run off a Lithium-Iodide battery, which gives a high amount of power but could only last approximately 2 to 5 years, requiring frequent replacement. However, replacement is unnecessary for betavoltaic cells as they can last at least 20 years. Commercially available tritium betavoltaic cells provided by City Labs Inc. were tested at a temperature range of -50°C to 150°C …
Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions,
2015
Purdue University
Effect Of Helium Ions Energy On Molybdenum Surfaces Under Extreme Conditions, Joseph Fiala, Jitendra K. Tripathi, Sean Gonderman, Ahmed Hassanein
The Summer Undergraduate Research Fellowship (SURF) Symposium
Plasma facing components (PFCs) in fusion devices must be able to withstand high temperatures and erosion due to incident energetic ion radiations. Tungsten has become the material of choice for PFCs due to its high strength, thermal conductivity, and low erosion rate. However, its surface deteriorates significantly under helium ion irradiation in fusion-like conditions and forms nanoscopic fiber-like structures, or fuzz. Fuzz is brittle in nature and has relatively lower thermal conductivity than that of the bulk material. Small amounts of fuzz may lead to excessive contamination of the plasma, preventing the fusion reaction from taking place. Despite recent efforts, …
Exploring The Effect Of Sample Properties On Spark-Induced Breakdown Spectroscopy,
2015
Purdue University
Exploring The Effect Of Sample Properties On Spark-Induced Breakdown Spectroscopy, Michael J. Marino, Payson Dieffenbach, Liesl A. Krause, Prasoon Diwakar, Ahmed Hassanein
The Summer Undergraduate Research Fellowship (SURF) Symposium
Optical emission spectroscopy techniques such as laser-induced breakdown spectroscopy (LIBS) and spark-induced breakdown spectroscopy (SIBS) provide portable and robust methods for elemental detection in real-time. Laser-produced emissions are then used for quantitative and qualitative analysis of a sample material with applications in explosives detection. For both techniques, the main obstacles have always been signal intensity, accuracy, and sensitivity of detection. The main advantage of the SIBS method is more safe operation, while still maintaining the portability of the technique. In this study, detailed characterization of spark induced plasma, analyte emission intensity, plasma temperature, electron density, and plasma persistence has been …
Effect Of Carbon Impurity On Molybdenum Nanostructure Evolution Under Helium Ion Irradiation In Extreme Conditions,
2015
Purdue University
Effect Of Carbon Impurity On Molybdenum Nanostructure Evolution Under Helium Ion Irradiation In Extreme Conditions, Nikhil A. Bharadwaj, Jitendra Tripathi, Ahmed Hassanein, Sean Gonderman
The Summer Undergraduate Research Fellowship (SURF) Symposium
The performance of plasma facing components (PFC) is of great important for the realization of prototype nuclear fusion. Tungsten has been considered as the leading high-Z PFC material for these reactors and tokamaks due to its superior thermophysical properties, high melting point, low sputtering yield, and low tritium inventory. However, its surface deteriorates significantly under helium ion irradiation in extreme (fusion) conditions and forms nanoscopic fiber like structures (fuzz) Recent studies show that the formation of fuzz nanostructure on tungsten can be suppressed by the presence of plasma impurities such as carbon and beryllium. In the present study, the effects …
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization,
2015
Purdue University
Optical Emission Spectroscopy Diagnostics Of Cold Plasmas For Food Sterilization, Abhijit Jassem, Michael Lauria, Russell Brayfield Ii, Kevin M. Keener, Allen L. Garner
The Summer Undergraduate Research Fellowship (SURF) Symposium
There is a growing need for economical, effective, and safe methods of sterilizing fresh produce. The most common method is a chlorine wash, which is expensive and may introduce carcinogens. High voltage cold atmospheric pressure plasmas are a promising solution that has demonstrated a germicidal effect; however, the responsible chemical mechanisms and reaction pathways are not fully understood. To elucidate this chemistry, we used optical emission spectroscopy to measure the species produced in the plasma generated by a 60 Hz pulsed dielectric barrier discharge in a plastic box containing various fill gases (He, N2, CO2, dry …
Design And Fabrication Of Liquid Scintillator Counter,
2015
California State University - Long Beach
Design And Fabrication Of Liquid Scintillator Counter, Andrea Calderon Saucedo, John L. Orrell
STAR Program Research Presentations
Pacific Northwest National Laboratory (PNNL) is currently developing an ultra-low background liquid scintillator counter (ULB LSC) in the shallow underground laboratory. At a depth of 35-meters water-equivalent, the underground laboratory has a multi-layered shielding to keep out cosmic-ray induced background. The ULB LSC, which is located in a clean room facility, is a multi-layered design made up of various materials, including plastic scintillator veto panels, borated polyethylene, lead and copper. These layers help lower the contributions of the terrestrial background and intrinsic background, resulting from the impurities present in the materials, to the overall background count rate observed by the …
Impurity Diffusion As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics,
2015
United States Military Academy
Impurity Diffusion As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall
International Journal of Nuclear Security
The ability to determine the age of seized nuclear material—that is, the time that has passed since it was formed— would provide crucial data to be used in its investigation. This paper reviews the methods and mathematical reasoning behind the use of diffusion theory, as previously applied to analysis of metals in ancient artifacts and other objects, to modern investigations in nuclear science. We here examine the time-dependent processes of diffusion, including grain boundary diffusion and discontinuous precipitation, and we assess the utility of examining the profiles of impurity and alloying element concentrations for use as a tool in pre-detonation …
Student Writing Competition,
2015
University of Tennessee, Knoxville
Student Writing Competition
International Journal of Nuclear Security
No abstract provided.
Cover,
2015
University of Tennessee, Knoxville
Masthead,
2015
University of Tennessee, Knoxville
From The Editor,
2015
University of Tennessee, Knoxville
The Nuclear Security Science And Policy Institute At Texas A&M University,
2015
Texas A&M University
The Nuclear Security Science And Policy Institute At Texas A&M University, Claudio A. Gariazzo, Kelley H. Ragusa, David R. Boyle, William S. Charlton, Sunil S. Chirayath, Craig M. Marianno, Paul Nelson Jr.
International Journal of Nuclear Security
The Nuclear Security Science and Policy Institute (NSSPI) is a multidisciplinary organization at Texas A&M University and was the first U.S. academic institution focused on technical graduate education, research, and service related to the safeguarding of nuclear materials and the reduction of nuclear threats. NSSPI employs science, engineering, and policy expertise to: (1) conduct research and development to help detect, prevent, and reverse nuclear and radiological proliferation and guard against nuclear terrorism; (2) educate the next generation of nuclear security and nuclear nonproliferation leaders; (3) analyze the interrelationships between policy and technology in the field of nuclear security; and (4) …
Addressing Imbalances In Us Nuclear Economic And Nonproliferation Policies,
2015
Institute for Nuclear Security
Addressing Imbalances In Us Nuclear Economic And Nonproliferation Policies, Matthew S. Duchene, Howard L. Hall
International Journal of Nuclear Security
Foreign civilian nuclear start-ups have an increasing number of international partners capable of supplying fuel cycle technologies. The desire to prevent the spread of dual-use enrichment and reprocessing technology by asking partner states to rely on international fuel markets is a major obstacle for US negotiating civilian nuclear trade agreements, leading to delays. US participation in emerging nuclear markets is being undercut by foreign competition, leading to decreasing economic competition and influence in international nonproliferation issues. It is therefore necessary for the US to reinvest and complete its domestic nuclear fuel cycle and modify its process for implementing civilian nuclear …
Radiation Damage As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics,
2015
United States Military Academy
Radiation Damage As A Possible Metal Chronometer For Pre-Detonation Nuclear Forensics, Edward T. Peskie, Howard L. Hall
International Journal of Nuclear Security
The better we can determine how long ago nuclear material was made, the sharper our tools for investigating seized nuclear materials. This paper examines the effects of radiation damage caused by the decay of uranium isotopes, and assesses how experts in nuclear forensics could use the analyses of these damaged regions to determine how much time has passed since metal samples were formed. It also draws parallels from fission track dating studies of mineral samples under geologic time, and proposes modifications to past publications on α-recoil track dating in order to determine the time since a metal sample was cast …
Coupling Nuclear Induced Phonon Propagation With Conversion Electron Mössbauer Spectroscopy,
2015
Air Force Institute of Technology
Coupling Nuclear Induced Phonon Propagation With Conversion Electron Mössbauer Spectroscopy, Michael J. Parker
Theses and Dissertations
Mössbauer spectroscopy is a very sensitive measurement technique (10-8 eV) which prompted motivation for the experiment described in this thesis. Namely, can a sensitive detection system be developed to detect nuclear recoils on the order of 10 to 100 of eVs? The hypothesis that this thesis tests is: Nuclear induced phonon bursts caused by Rutherford scattered alphas, decayed from 241Am, in a type-310 stainless steel material can couple with 7.3 keV conversion electron Mössbauer events at the other end of the material which will have a statistically significant effect on a Mössbauer spectrum. The phonon bursts produced by …
Well-Posedness And Convergence Of Cfd Two-Fluid Model For Bubbly Flows,
2015
Purdue University
Well-Posedness And Convergence Of Cfd Two-Fluid Model For Bubbly Flows, Avinash Vaidheeswaran
Open Access Dissertations
The current research is focused on developing a well-posed multidimensional CFD two-fluid model (TFM) for bubbly flows. Two-phase flows exhibit a wide range of local flow instabilities such as Kelvin-Helmholtz, Rayleigh-Taylor, plume and jet instabilities. They arise due to the density difference and/or the relative velocity between the two phases. A physically correct TFM is essential to model these instabilities. However, this is not the case with the TFMs in numerical codes, which can be shown to have complex eigenvalues due to incompleteness and hence are ill-posed as initial value problems. A common approach to regularize an incomplete TFM is …
Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide,
2015
Air Force Institute of Technology
Surface Geometry And Chemistry Of Hydrothermally Synthesized Single Crystal Thorium Dioxide, Scott W. Key
Theses and Dissertations
The surface chemistry and geometry of hydrothermally grown, single crystal ThO2 was studied using X-ray Photoemission Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The crystal was studied before and after sputter etching with Ar+, heating up to 675 K, and dehydration with dry nitrogen. The hydrothermal growth technique incorporated Cs and F into the near surface bulk. Heating to 675 K drove off the F, but did not the Cs. Sputtering with Ar+ at 75° cleaned the crystal and created a more uniform surface geometry. The Th 4f peak resolution, as measured by XPS improved by …
The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport,
2015
Air Force Institute of Technology
The Effect Of Anisotropic Scatter On Atmospheric Neutron Transport, Nicholas J. Mcintee
Theses and Dissertations
Anisotropy is present in the angular distributions of neutrons departing from a nuclear scattering event. This anisotropy cannot be defined in a closed-form solution, and it is dependent on the incident neutron energy, elastic or inelastic scatter, along with the inelastic level, and the species struck. The underlying question is, if anisotropic behavior is worth the computational cost to be included in certain simulations, and if so, what level of precision is effected by the inclusion of anisotropic scatter. A Watt spectrum of U235 fission neutrons was examined as it collided with species in a nitrogen-oxygen atmosphere. In a …
