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Articles 1 - 8 of 8
Full-Text Articles in Instrumentation
Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice
Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice
Geology Faculty Publications
The Three-Axis N-sample Automated Goniometer for Evaluating Reflectance (TANAGER) is a custom goniometer designed to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER interfaces with a Malvern Panalytical ASD Fieldspec 4 Hi-Res reflectance spectrometer to collect data from 350-2500 nm at a range of incidence, emission and azimuth angles. To validate the accuracy and repeatability of data collected with TANAGER - and to characterize any instrument noise, artifacts or sample heating effects - we collected spectra from three categories of targets: (1) powdered calcium sulfate (anhydrite), (2) naturally weathered basalt surfaces, and (3) color calibration …
Characterizing Plasma With Emission Tomography-Feasibility Study On Synthetic And Experimental Data, M. Nikolić, A. Samolov, A. Godunov, L. Vušković,, S. Popović
Characterizing Plasma With Emission Tomography-Feasibility Study On Synthetic And Experimental Data, M. Nikolić, A. Samolov, A. Godunov, L. Vušković,, S. Popović
Physics Faculty Publications
We present a feasibility study on different tomographic algorithms to overcome the issues of finite sets of projection data, limited viewing angles, and noisy data, which cause the tomographic reconstruction to be an ill-posed inversion problem. We investigated three approaches: single angle Abel inversion, two angle approach, and multiple angle 2D plasma tomography. These methods were tested on symmetric and asymmetric sample functions and on experimental results from a supersonic flowing argon microwave plasma sustained in a cylindrical quartz cavity. The analysis focused on the afterglow region of the microwave flow where a plasmoid-like formation was observed. We investigated the …
Automated Spectroscopic Detection And Mapping Using Alma And Machine Learningtechniques, Steven Cocke, Andrew Wilkins, Josephine Mcdaniel, John Santerre, Conor Nixon
Automated Spectroscopic Detection And Mapping Using Alma And Machine Learningtechniques, Steven Cocke, Andrew Wilkins, Josephine Mcdaniel, John Santerre, Conor Nixon
SMU Data Science Review
In this paper we present a methodology for automating theclassification of spectrally resolved observations of multiple emissionlines with the Atacama Large Millimeter/submillimeter Array (ALMA).Molecules in planetary atmospheres emit or absorb different wavelengthsof light thereby providing a unique signature for each species. ALMAdata were taken from interferometric observations of Titan made be-tween UT 2012 July 03 23:22:14 and 2012 July 04 01:06:18 as part ofALMA project 2011.0.00319.S. We first employed a greedy set cover algorithm to identify the most probable molecules that would reproducethe set of frequencies with respective flux greater than 3σaway from themean. We then selected a subset of …
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
Ted von Hippel
It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual …
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers, Charles R. Markus, Adam J. Perry, James N. Hodges, Benjamin J. Mccall
Improving Cavity Enhanced Spectroscopy Of Molecular Ions In The Mid-Infrared With Up-Conversion Detection And Brewster-Plate Spoilers, Charles R. Markus, Adam J. Perry, James N. Hodges, Benjamin J. Mccall
Chemistry & Biochemistry Faculty Publications
The performance of sensitive spectroscopic methods in the mid-IR is often limited by fringing due to parasitic etalons and the background noise in mid-infrared detectors. In particular, the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS), which is capable of determining the frequencies of strong rovibrational transitions of molecular ions with sub-MHz uncertainty, needs improved sensitivity in order to probe weaker transitions. In this work, we have implemented up-conversion detection with NICE-OHVMS in the 3.2 - 3.9 μm region to enable the use of faster and more sensitive detectors which cover visible wavelengths. The higher bandwidth enabled …
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
The Power Of Principled Bayesian Methods In The Study Of Stellar Evolution, Ted Von Hippel, David Van Dyk, David Stenning, Elliot Robinson, Elizabeth Jeffery, Nathan Stein, William Jefferys, Erin M. O'Malley
Publications
It takes years of effort employing the best telescopes and in- struments to obtain high-quality stellar photometry, astrometry, and spectroscopy. Stellar evolution models contain the experience of life- times of theoretical calculations and testing. Yet most astronomers fit these valuable models to these precious datasets by eye. We show that a principled Bayesian approach to fitting models to stellar data yields substantially more information over a range of stellar astrophysics. We highlight advances in determining the ages of star clusters, mass ratios of binary stars, limitations in the accuracy of stellar models, post-main-sequence mass loss, and the ages of individual …
Design And Evaluation Of A Fiber Optic Probe As A Means Of Subsurface Planetary Exploration, Robert Paul Pilgrim
Design And Evaluation Of A Fiber Optic Probe As A Means Of Subsurface Planetary Exploration, Robert Paul Pilgrim
Graduate Theses and Dissertations
The Optical Probe for Regolith Analysis (OPRA) is an instrumentation concept designed to provide spectroscopic analysis of the near subsurface of unconsolidated regolith on bodies such as moons, asteroids and planets. Below a chemically altered surface may lay the geological history in the form of stratigraphy that is shielded from degradation due to harsh external environments. Most of what we know about our solar system comes from remote platforms, such as satellites that are deployed into orbit around the target body. In the case of Mars, we have had several successful landers and rovers however, with the exception of the …
Moderate-Resolution Spectroscopy Of The Lensed Quasar 2237+0305: A Search For Ca Ii Absorption Due To The Interstellar Medium In The Foreground Lensing Galaxy, P. Hintzen, S. P. Maran, A. G. Michalitsianos, C. B. Foltz, F. H. Chafee, Menas Kafatos
Moderate-Resolution Spectroscopy Of The Lensed Quasar 2237+0305: A Search For Ca Ii Absorption Due To The Interstellar Medium In The Foreground Lensing Galaxy, P. Hintzen, S. P. Maran, A. G. Michalitsianos, C. B. Foltz, F. H. Chafee, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The gravitational lens system 2237 + 0305 consists of a low-redshift barred spiral galaxy (z = 0.0394) centered on a more distant quasar (z = 1.695). Because the lensing galaxy is nearly face on, spectroscopy of the background quasar affords a unique opportunity to study the interstellar medium in the galaxy's center and buW:. We report moderate-resolution spectroscopy of QS02237 + 0305 yielding a 3u upper limit of 72 rnA forthe rest equivalent width of Ca II K absorption d);le to gas in the intervening galaxy. Since gas in the Milky Way "thick disk" typically produces 220 mA Ca II …