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Articles 1 - 12 of 12
Full-Text Articles in Physical Sciences and Mathematics
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 …
Calibration Of The Lux-Zeplin Dual-Phase Xenon Time Projection Chamber With Internally Injected Radioisotopes, Christopher D. Nedlik
Calibration Of The Lux-Zeplin Dual-Phase Xenon Time Projection Chamber With Internally Injected Radioisotopes, Christopher D. Nedlik
Doctoral Dissertations
Self-shielding in ton-scale liquid xenon (LXe) detectors presents a unique challenge for calibrating detector response to interactions in the detector's innermost volume. Calibration radioisotopes must be injected directly into the LXe to reach the central volume, where they must either decay away with a short half life or be purified out. We present an overview of, and results from, the prototype source injection system (SIS) developed at the University of Massachusetts Amherst for the LUX-ZEPLIN experiment (LZ). The SIS is designed to refine techniques for the injection and removal of precise activities of various calibration radioisotopes that are useful in …
Development And Distribution Of Thermometry Hardware For The Simons Observatory, Samuel Day-Weiss
Development And Distribution Of Thermometry Hardware For The Simons Observatory, Samuel Day-Weiss
The Yale Undergraduate Research Journal
The Simons Observatory (SO) is a new cosmic microwave background (CMB) experiment consisting of four telescopes. SO is being constructed at an elevation of 5,190 meters on Cerro Toco in the Atacama Desert in Chile, and is set to begin observation in 2022. SO will employ 60,000 detectors, yielding a sensitivity greater than all previous CMB experiments. To achieve low noise performance the telescope cryostats will be cooled to ~100 mK using low temperature dilution refrigerators. Measuring cryostat temperatures is essential for pre-deployment testing, telescope installation, and telescope monitoring during observation. The purpose of this project is to design, build, …
Absolute Power Measurements For Advanced Ligo Photon Calibrator, Francisco Llamas Villarreal
Absolute Power Measurements For Advanced Ligo Photon Calibrator, Francisco Llamas Villarreal
Theses and Dissertations
Since its first detection in 2015, the Light Interferometer Gravitational-Wave Observatory has been notably recognized for the successful measurement of gravitational waves. The successful detection of gravitational-waves comes from the effort of more than a thousand scientist working in collaboration. To characterize the change in displacement of the ETMs, LIGO uses several methods of calibration. The Photon Calibrator has gained significance to the point of becoming the primary calibration tool for the Advanced LIGO detectors. Relying on photon radiation pressure to calibrate the interferometer, the photon calibrator measures the change in displacement of the ETM in relation to the power …
Radiometric Stability Of The Saber Instrument, Martin G. Mlynczak, Taumi Daniels, Linda A. Hunt, Jia Yue, B. Thomas Marshall, James M. Russell Iii, Ellis E. Remsburg, Joseph Tansock, Roy Esplin, Mark Jensen, Andrew Shumway, Larry Gordley, J. -H. Yee
Radiometric Stability Of The Saber Instrument, Martin G. Mlynczak, Taumi Daniels, Linda A. Hunt, Jia Yue, B. Thomas Marshall, James M. Russell Iii, Ellis E. Remsburg, Joseph Tansock, Roy Esplin, Mark Jensen, Andrew Shumway, Larry Gordley, J. -H. Yee
Space Dynamics Laboratory Publications
The SABER instrument on the National Aeronautics and Space Administration Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics satellite continues to provide a long‐term record of Earth's stratosphere, mesosphere, and lower thermosphere. The SABER data are being used to examine long‐term changes and trends in temperature, water vapor, and carbon dioxide. A tacit, central assumption of these analyses is that the SABER instrument radiometric calibration is not changing with time; that is, the instrument is stable. SABER stratospheric temperatures and those derived from Global Positioning System Radio Occultation measurements are compared to examine SABER's stability. Global Positioning System Radio Occultation measurements are inherently stable …
Calibration Transients In Ligo Detectors, Thomas Daniel Abbott
Calibration Transients In Ligo Detectors, Thomas Daniel Abbott
LSU Doctoral Dissertations
This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and …
The Acs Survey Of Globular Clusters. Xiii. Photometric Calibration In Comparison With Stetson Standards, Maren Hempel, Ata Sarajedini, Jay Anderson, Antonio Aparicio, Luigi R. Bedin, Brian Chaboyer
The Acs Survey Of Globular Clusters. Xiii. Photometric Calibration In Comparison With Stetson Standards, Maren Hempel, Ata Sarajedini, Jay Anderson, Antonio Aparicio, Luigi R. Bedin, Brian Chaboyer
Dartmouth Scholarship
In this study we compare the photometric data of 34 Milky Way globular clusters, observed within the Advanced Camera for Surveys (ACS) Treasury Program (PI: A. Sarajedini) with the corresponding ground-based data, provided by the Photometric Standard Field Catalogs of Stetson. We focus on the transformation between the Hubble Space Telescope/ACS F606W to V-band and F814W to I-band only. The goal is to assess the validity of the filter transformation equations by Sirianni et al. with respect to their dependence on metallicity, horizontal branch morphology, mass, and integrated (V – I) color of the various …
Experimental Analysis Of Energy-Based Acoustic Arrays For Measurement Of Rocket Noise Fields, Jarom Henry Giraud
Experimental Analysis Of Energy-Based Acoustic Arrays For Measurement Of Rocket Noise Fields, Jarom Henry Giraud
Theses and Dissertations
Microphone arrays are useful for measuring acoustic energy quantities (e.g. acoustic intensity) in the near-field of a full-scale solid rocket motor. Proper characterization of a rocket plume as a noise source will allow for more accurate predictions in engineering models that design for protection of structures, payloads and personnel near the rockets. Acoustic intensity and energy density quantities were measured in three rocket noise fields and have shown that the apparent source region of the rocket becomes smaller and moves upstream as frequency increases. Theoretical results accounting for some scattering and finite-difference errors arising in these types of energy-based measurements …
The Metallicity Of The Cm Draconis System, Ryan C. Terrien, Scott W. Fleming, Suvrath Mahadevan, Rohit Deshpande, Gregory A. Feiden
The Metallicity Of The Cm Draconis System, Ryan C. Terrien, Scott W. Fleming, Suvrath Mahadevan, Rohit Deshpande, Gregory A. Feiden
Dartmouth Scholarship
The CM Draconis system comprises two eclipsing mid-M dwarfs of nearly equal mass in a 1.27-day orbit. This well-studied eclipsing binary has often been used for benchmark tests of stellar models, since its components are amongst the lowest mass stars with well-measured masses and radii (~ 1% relative precision). However, as with many other low-mass stars, non-magnetic models have been unable to match the observed radii and effective temperatures for CM Dra at the 5-10% level. To date, the uncertain metallicity of the system has complicated comparison of theoretical isochrones with observations. In this Letter, we use data from the …
Photometric Calibrations For 21st Century Science, Stephen M. Kent, Terry D. Oswalt, Mary Elizabeth Kaiser, Et Al.
Photometric Calibrations For 21st Century Science, Stephen M. Kent, Terry D. Oswalt, Mary Elizabeth Kaiser, Et Al.
Publications
The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. We stress the …
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Correlation Analysis Of Sfi Peculiar Velocities, Stefano Borgani, Luiz N. Da Costa, Idit Zehavi, Riccardo Giovanelli, Martha P. Haynes, Wolfram Freudling, Gary Wegner, John J. Salzer
Dartmouth Scholarship
We present results of a statistical analysis of the SFI catalog of peculiar velocities, a recently completed survey of spiral field galaxies with I-band Tully-Fisher distances. The velocity field statistic utilized is the velocity correlation function, ψ1(r), originally introduced by Górski et al. The analysis is performed in redshift space so as to circumvent potential ambiguities connected with inhomogeneous Malmquist bias corrections. The results from the SFI sample are compared with linear-theory predictions for a class of cosmological models. We generate a large set of mock samples, extracted from N-body simulations, which are used …
Very High Pressure Effects Upon The Epr Spectrum Of Ruby, H. Mark Nelson, D. B. Larson, J. H. Gardner
Very High Pressure Effects Upon The Epr Spectrum Of Ruby, H. Mark Nelson, D. B. Larson, J. H. Gardner
Faculty Publications
The variation in the electron paramagnetic resonance (EPR) spectrum of ruby as a function of pressure has been observed to beyond 70 kbar for a magnetic field orientation parallel to the crystalline c axis. The data can be interpreted in terms of the usual spin Hamiltonian, where the spectroscopic splitting factor g|| has the same value as at ambient pressures, but where the zero-field splitting deltaincreases in a linear fashion from 0.38 to 0.43 cm. The experimental apparatus has been described previously, although important improvements in the pressure seal and in the pressure calibration have been made and are described …