A Statistical Approach To Fusing 2-D And 3-D Ladar Systems,
2011
Air Force Institute of Technology
A Statistical Approach To Fusing 2-D And 3-D Ladar Systems, Paul F. Dolce
Theses and Dissertations
LADAR (LAser Detection and Ranging) systems can be used to provide 2-D and 3-D images of scenes. Generally, 2-D images possess superior spatial resolution but without range data due to the density of their focal plane arrays. A 3-D LADAR system can produce range to target data at each pixel, but lacks the 2-D system's superior spatial resolution. The 3-D system is limited by its hardware, specifically its imaging array. Currently developers are investigating ways to change the pixel size in the 3-D LADAR imaging array, but the costs of this research is quite expensive and technically robust. It is …
Shack-Hartmann And Interferometric Hybrid Wavefront Sensor,
2011
Air Force Institute of Technology
Shack-Hartmann And Interferometric Hybrid Wavefront Sensor, Troy R. Ellis
Theses and Dissertations
This document reports results of wave-optics simulations used to test the performance of a hybrid wavefront sensor designed to combine the self-referencing interferometer and Shack-Hartmann wavefront sensors in an optimal way. Optimal hybrid-wavefront sensor design required a thorough analysis of the noise characteristics of each wavefront sensor to produce noise models that assist in the design of an optimal phase-estimation algorithm. Feasible architectures and algorithms for combining wavefront sensors were chosen, and the noise models of the individual wavefront sensors were combined to form a model for the noise-induced error of the resulting hybrid sensor. The hybrid wavefront sensor and …
A Multispectral Bidirectional Reflectance Distribution Function Study Of Human Skin For Improved Dismount Detection,
2011
Air Force Institute of Technology
A Multispectral Bidirectional Reflectance Distribution Function Study Of Human Skin For Improved Dismount Detection, Bradley M. Koch
Theses and Dissertations
In 2008, the Sensors Exploitation Research Group at the Air Force Institute of Technology began using spectral properties of skin for the detection and classification of humans. Since then a multispectral skin detection system was developed to exploit the optical properties of human skin at wavelengths in the visible and near infrared region of the electromagnetic spectrum. A rules-based detector, analyzing an image spectrally, currently bases its skin pixel selection criteria on a diffuse skin reflectance model. However, when observing skin in direct view of the sun, a glint of light off skin is common and indicates specularity. The areas …
Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques,
2011
Air Force Institute of Technology
Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques, Jeremiah D. Johnson
Theses and Dissertations
Navigation in indoor and urban environments by small unmanned systems is a topic of interest for the Air Force. The Advanced Navigation Technology Center at the Air Force Institute of Technology is continually looking for novel approaches to navigation in GPS deprived environments. Inertial sensors have been coupled with image aided concepts, such as feature tracking, with good results. However, feature density in areas with large, flat, smooth surfaces tends to be low. Polarimetric sensors have been used for surface reconstruction, surface characterization and outdoor navigation. This thesis combines aspects of some of these algorithms along with a realistic, micro-facet …
Effect Of Coudé Pupil Rotation On Sodium Laser Beacon Perspective Elongation,
2011
Air Force Institute of Technology
Effect Of Coudé Pupil Rotation On Sodium Laser Beacon Perspective Elongation, Russell J. Mcguigan
Theses and Dissertations
This research models a sodium laser guide star and its measurement by a Shack-Hartmann wavefront sensor. By predicting the extent of beacon elongation and Coude rotation, reference images are produced for each subaperture throughout an engagement scenario. These reference sources are then used to continuously recalibrate the system as it changes orientation. This model measures the effect of perspective elongation and Coude on SHWFS measurements to quantitatively determine the extent of degradation that occurs.
Optical Metamaterial Design, Fabrication And Test,
2011
Air Force Institute of Technology
Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi
Theses and Dissertations
Metamaterials, materials that make use of naturally occurring materials and designed structures to create materials with special properties not found in nature, are a fascinating new area of research, combining the fields of physics, microfabrication, and material science. This work will focus on the development of metamaterials operating in the visible and infrared which will be constructed and tested for basic optical properties. Possible applications for these materials will not be investigated. The this work will go into the fabrication and test of layered metal-dielectric structures, called layered metamaterials, as these structures hold potential for applications in advanced optical systems. …
Background And Source Term Identification In Active Neutron Interrogation Methods,
2011
Air Force Institute of Technology
Background And Source Term Identification In Active Neutron Interrogation Methods, David A. Anthony
Theses and Dissertations
The detection and tracking of special nuclear material (SNM) is vitally important in order to know where these materials are and prevent them from being used in a harmful manner. Active neutron interrogation is a sought after method for this since the resulting high energy gamma rays produced by inelastic scattering and neutron capture reactions can pass through denser shielding than natural decay gammas, and their energy spectra are unique to each isotope. Using Monte Carlo N Particle (MCNP) simulations, this research investigated the characterization of gamma ray sources created by active neutron interrogation. Ring detector and mesh tallies within …
Combined Effects Of Radio Frequency And Electron Radiation On Cmos Inverters,
2011
Air Force Institute of Technology
Combined Effects Of Radio Frequency And Electron Radiation On Cmos Inverters, Kristofer R. Dahl
Theses and Dissertations
This research examines the measurement methodology, and the results of, the combined effects of electron and radio frequency irradiation (500kHz) on a CMOS Hex Inverter, CD4069UB. There have been many studies in recent years on the effects of electron radiation and electromagnetic interference on integrated circuits, however the combined effects have not been measured. A major obstacle for in-situ electron irradiation experiments is the over current hazard that exists to measurement equipment that comes from taking real-time, in-situ measurements. To overcome this, a test circuit was designed and built to allow for real-time in-situ measurement of the output voltage, current …
Cathodoluminescence And Photoemission Of Doped Lithium Tetraborate,
2011
Air Force Institute of Technology
Cathodoluminescence And Photoemission Of Doped Lithium Tetraborate, Christina L. Dugan
Theses and Dissertations
Lithium tetraborate (Li2B4O7) crystals are being developed for possible use in solid state neutron detectors. The 6Li(n,α)3H and 10B(n,α)7Li reactions are the basis for neutron detection, and a Li2B4O7 crystal enriched with Mn should show improved efficiency for neutron detection. There is a lack of fundamental characterization information regarding this useful material, particularly with regard to its electronic configuration. Photoemission spectroscopy was used to determine the energy level structure of the Mn doped Li2B4O7 crystals. …
Changes To Electrical Conductivity In Irradiated Carbon Nanocomposites,
2011
Air Force Institute of Technology
Changes To Electrical Conductivity In Irradiated Carbon Nanocomposites, Nickolas A. Duncan
Theses and Dissertations
Carbon nanotubes (CNT) and carbon nanofibers (CNF) are two nanoparticles incorporated in a polymer to create a composite material. These composites are two potential lightweight materials for use as replacements for aluminum structures on satellite systems. Both composite materials have a low resistivity that is consistent with conductive materials. However, the CNT composite is substantially more conductive than the CNF composite. The CNT and CNF composites were irradiated with electrons and neutrons to fluence levels of and. No changes were observed in the resistivity of the CNF composites following neutron and electron irradiation. A 3.7% increase in resistivity was observed …
Radiation Effects On The Electrical Properties Of Hafnium Oxide Based Mos Capacitors,
2011
Air Force Institute of Technology
Radiation Effects On The Electrical Properties Of Hafnium Oxide Based Mos Capacitors, Jesse C. Foster
Theses and Dissertations
Hafnium oxide-based MOS capacitors were investigated to determine electrical property response to radiation environments. In situ capacitance versus voltage measurements were analyzed to identify voltage shifting as a result of changes to trapped charge with increasing dose of gamma, neutron, and ion radiation. In situ measurements required investigation and optimization of capacitor fabrication to include dicing, cleaning, metalization, packaging, and wire bonding. A top metal contact of 200 angstroms of titanium followed by 2800 angstroms of gold allowed for repeatable wire bonding and proper electrical response. Gamma and ion irradiations of atomic layer deposited hafnium oxide on silicon devices both …
Diffusion Of Rubidium Vapor Through Hollow-Core Fibers For Gas-Phase Fiber Lasers,
2011
Air Force Institute of Technology
Diffusion Of Rubidium Vapor Through Hollow-Core Fibers For Gas-Phase Fiber Lasers, Eric M. Guild
Theses and Dissertations
This work examines the diffusion of rubidium through a small diameter tube alone and in the presence of noble gases. A fluid dynamics analysis is investigated to aid in choosing a method for transferring atomic rubidium vapor that is reliable and efficient. Solutions to the time dependant ordinary differential equation describing the experimental flow properties of the system reveal more precise outcomes than previously practiced routines. Resolved viscosities and Poiseuille flow theory velocity profile distributions are characterized for noble gas carriers of the rubidium vapor. Applying Reynolds Numbers to the flow experiments provides pressure differential boundaries that are employed in …
Characterization Of The Neutron Spectrum At The Indiana University Nrep Neutron Source,
2011
Air Force Institute of Technology
Characterization Of The Neutron Spectrum At The Indiana University Nrep Neutron Source, Matthew R. Halstead
Theses and Dissertations
The neutron source at the Indiana University Cyclotron Facility produces neutrons via proton bombardment of a natural beryllium (100% 9Be) target. This source has two beam lines: the LENS and the NREP. The energy spectrum of the neutrons produced on the NREP beam line has not yet been characterized. Through simulation using the GEANT and MCNP particle transport codes as well as neutron activation analysis experiments, an attempt was made to characterize the energy spectrum of the neutron production source. First, the neutron production spectrum of beryllium, simulated using GEANT, was compared with literature; there are significant deviations. Next, foils …
Remote Quantification Of Smokestack Total Effluent Mass Flow Rates Using Imaging Fourier-Transform Spectroscopy,
2011
Air Force Institute of Technology
Remote Quantification Of Smokestack Total Effluent Mass Flow Rates Using Imaging Fourier-Transform Spectroscopy, Jacob L. Harley
Theses and Dissertations
A Telops Hyper-Cam midwave infrared (1.5 − 5.5μm) imaging Fourier-transform spectrometer (IFTS) was used to estimate industrial smokestack total effluent mass flow rates by combining spectrally-determined species concentrations with flow rates estimated via analysis of sequential images in the raw interferogram cube. Strong emissions from H2O, CO2, CO, SO2, and NO were observed in the spectrum. A previously established plume radiative transfer model was used to estimate gas concentrations, and a simple temporal cross-correlation analysis of sequential imagery enabled an estimation of the flow velocity. Final effluent mass flow rates for CO2 and …
Ray Next Event Estimator Transport Of Primary And Secondary Gamma Rays,
2011
Air Force Institute of Technology
Ray Next Event Estimator Transport Of Primary And Secondary Gamma Rays, Whitman T. Dailey
Theses and Dissertations
This thesis investigated the application of the ray next event estimation Monte Carlo method to the transport of primary and secondary gamma rays. The problem of interest was estimation of the free field flux at a distant point in a vacuum from a point source in the atmosphere. An existing Fortran code for neutron transport, Ray Next-Event Estimator v4.0, was adapted to perform photon transport computations including coherent scattering, incoherent scattering, photoelectric absorption, and pair production interactions. Production and transport of secondary gamma rays produced in bremsstrahlung, neutron inelastic scatter, and neutron absorption interactions was also implemented. A new version …
Characterization Of A Boron Carbide Heterojunction Neutron Detector,
2011
Air Force Institute of Technology
Characterization Of A Boron Carbide Heterojunction Neutron Detector, James E. Bevins
Theses and Dissertations
New methods for neutron detection have become an important area of research in support of national security objectives. In support of this effort, p-type B5C on n-type Si heterojunction diodes have been built and tested. This research sought to optimize the boron carbide (BC) diode by coupling the nuclear physics modeling capability of GEANT4 and TRIM with the semiconductor device simulation tools. Through an iterative modeling process of controllable parameters, optimal device construction was determined such detection efficiency and charge collection were optimized. This allows an estimation of expected charge collection and efficiency given a set of operating …
Directional Pair-Production Spectrometer Design For Airborne Stand-Off Detection Of Special Nuclear Material,
2011
Air Force Institute of Technology
Directional Pair-Production Spectrometer Design For Airborne Stand-Off Detection Of Special Nuclear Material, William L. Harrell
Theses and Dissertations
The purposes of this research are to experimentally and theoretically prove the concept of a directional pair-production spectrometer to detect and locate the tailings that are created when making Special Nuclear Material (SNM) at stand-off distances from a remotely piloted vehicle (RPV). A directional pair-production spectrometer uses the information garnered from the high energy gamma rays emitted by these SNM manufacturing tailings to perform pair-production spectroscopy and identify the isotope of interest. Through simultaneous operation as a Compton camera, the detection system will be able to measure rudimentary directional information from the medium energy gamma decays. The detector used for …
Sensitivity Analysis Of Empirical Parameters In The Ionosphere-Plasmasphere Model,
2011
Air Force Institute of Technology
Sensitivity Analysis Of Empirical Parameters In The Ionosphere-Plasmasphere Model, Janelle V. Jenniges
Theses and Dissertations
A sensitivity analysis of empirical parameters used in physics-based models was completed in this study to determine their effect on electron densities and total electron content (TEC) in the ionosphere. The model used was the Ionosphere-Plasmasphere Model (IPM) developed by Utah State University. The empirical parameters studied include the O+/O collision frequency, zonal wind, secondary electron production, nighttime ExB drifts, and tidal structure. The sensitivity analysis was completed by comparing a default run of the IPM to a run with the parameter adjusted for three geophysical cases. Many of the comparisons resulted in nonlinear changes to the model …
Tof-Sims For Rapid Nuclear Forensics Evaluation Of Uranium Oxide Particles,
2011
Air Force Institute of Technology
Tof-Sims For Rapid Nuclear Forensics Evaluation Of Uranium Oxide Particles, Hannah E. Hocking
Theses and Dissertations
Because of nuclear proliferation concerns, nuclear material must be safeguarded, and peaceful intentions verified. The field of nuclear forensics addresses these concerns. While established nuclear forensic techniques exist, quicker, more accurate and less expensive methods are of interest for nonproliferation applications. Currently a host of different analytical techniques, requiring a week or longer, are employed to obtain isotopic ratios, chemical abundances and morphology for forensic particulate samples. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a candidate technology for rapid evaluation of these properties for small amounts of nuclear materials. After a thorough investigation, this study found TOF-SIMS to be particularly …
Investigation Of Yag:Ce Scintillating Fiber Properties Using Silicon Photomultipliers,
2011
Air Force Institute of Technology
Investigation Of Yag:Ce Scintillating Fiber Properties Using Silicon Photomultipliers, Bradley S. Jones
Theses and Dissertations
The properties of thin, cerium activated, yttrium aluminum garnet (YAG:Ce), scintillating fiber-shaped crystals were investigated for particle tracking and calorimetric applications such as Compton imaging of Special Nuclear Material from remote platforms at standoff ranges. Silicon photomultipliers (SiPMs) are relatively new, efficient, single photon sensitive, solid-state photodiode arrays which are well suited for the readout of scintillating fibers. Using SiPMs, the scintillation decay time profiles of six 400 micrometers YAG:Ce fiber crystals were measured under alpha and gamma irradiation. Interestingly, the observed decay times in the thin fibers were substantially slower than values for bulk single crystal YAG:Ce reported in …
