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Full-Text Articles in Physics
Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith
Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith
UNLV Theses, Dissertations, Professional Papers, and Capstones
This dissertation explores the use of UV-Visible spectroscopy and Time Resolved Laser Induced Fluorescence spectroscopy as near real time process monitors of uranium and plutonium concentrations in aqueous reprocessing trains. The molar absorptivities and linear ranges of these metals were investigated under total nitrate and acid concentrations similar to those found in current reprocessing systems. Concurrent to this, a new multiple wavelength monitor was derived that is capable of determining the total nitrate concentration spectroscopically. This method uses the uranium absorbance spectrum to calculate the nitrate concentration in solution. When used as part of an Advanced Safeguard suite, this technique …
Positron Annihilation Ratio Spectroscopy (Psars) Applied To Positronium Formation Studies, Robert C. Slaughter
Positron Annihilation Ratio Spectroscopy (Psars) Applied To Positronium Formation Studies, Robert C. Slaughter
Theses and Dissertations
A Positron Annihilation of Radiation Spectrometer (PsARS) was developed and characterized. PsARS spectroscopy as well as digital Positron Annihilation Lifetime Spectroscopy (PALS) was applied to measure positronium formation on gold nanoparticles deposited through an evaporative method onto a thin capillary tube. This gold coated capillary tube was designed to be used for positronium lifetime studies in local electric field experiments. High local electric fields can polarize a positron-electron pair, which may result in an extended lifetime of the positron. These fields may be created through the interaction of an external electric field with silver nanoparticles deposited onto the surface of …
Hard Collisions In Rubidium Using Sub-Doppler Spectroscopy, Douglas E. Thornton
Hard Collisions In Rubidium Using Sub-Doppler Spectroscopy, Douglas E. Thornton
Theses and Dissertations
To better understand the laser kinetics of an alkali gain medium, hard collisions, or velocity-changing collisions, has been studied and a velocity-changing collisional rate has been calculated. Previous works have studied these collisions, but no rate has been calculated. Using the precise tool of sub-Doppler spectroscopy, atomic hard collisions can be observed. The collected spectra are fitted with two different line shapes to demonstrate the accuracy of this method. From the fits, the number of hard collisions can be extracted. The time scale of the hard collisions in rubidium is interpolated by varying the chopping frequency of the pump beam, …
A Study Of The Irradiance-And-Temperature-Dependence Of Mid-Wave-Infrared (Mwir)Absorption In Indium Antimonide (Insb), John M. Callahan
A Study Of The Irradiance-And-Temperature-Dependence Of Mid-Wave-Infrared (Mwir)Absorption In Indium Antimonide (Insb), John M. Callahan
Theses and Dissertations
This work entails further investigation of the absorption of photons in indium antimonide (InSb). Previously work at the Air Force Institute of Technology (AFIT) attributed laser blooming effects in InSb focal plane arrays (FPA’s) to the Burstein-Moss effect. The contributing effect is from a decrease in the absorption of the InSb material, such that the transmitted optical energy scatters off the integrated circuitry beneath the InSb thin film back into the optical system. To evaluate this, irradiance-dependent laser-absorption experiments were performed on thinned, InSb wafers prior to their FPA fabrication. The samples were illuminated with a focused CO2 laser at …
Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill
Search For Novel Molecular Species Formed By Cold Rydberg Atoms In A Magneto-Optical Trap, Alexander Gill
Honors Theses
This describes a search for novel ultra-long-range molecular resonances between rubidium Rydberg atoms in a magneto-optical trap (MOT). We use the technique of photoassociative spectroscopy by directly scanning the wavelength of our Rydberg excitation laser about a 5p3/2 - 90p3/2 transition in a weak electric field and by scanning mm-waves about a 39sl/2 - 39p3/2 transition. The results of both of these surveys are inconclusive.
Hyperspectral Analysis Of Space Objects: Signal To Noise Evaluation, Daniel Hrovat
Hyperspectral Analysis Of Space Objects: Signal To Noise Evaluation, Daniel Hrovat
Theses and Dissertations
Hyperspectral analysis of space objects is being considered as a means of enhancing Space Object Identification. SOI capabilities. This study develops a mathematical simulation based on fundamental radiometry principles to evaluate the feasibility of hyperspectral analysis of space objects. The study uses Signal to Noise Ratio SNR as the basis for the feasibility evaluation, and addresses the question Is there enough target signal in narrow wavelength bandwidths to conduct hyperspectral measurements of space objects The analysis characterizes the target signal and noise sources using fundamental radiometry, and develops a flexible radiometry model which calculates the target signal count rate, and …