ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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Description
The Milky Way galaxy is a powerful dynamic system that is highly efficient at recycling material. Stars are born out of intergalactic gas and dust, fuse light elements into heavier elements in their cores, then upon stellar death spread material throughout the galaxy, either by diffusion of planetary nebula or by explosive events for high mass stars, and that gas must cool and condense to form stellar nurseries. Though the stellar lifecycle has been studied in detail, relatively little is known about the processes by which hot, diffuse gas ejected by dying stars cools and conglomerates in the interstellar medium (ISM). Much of this mystery arises because only recently have instruments with sufficient spatial and spectral resolution, sensitivity, and bandwidth become available in the terahertz (THz) frequency spectrum where these clouds peak in either thermal or line emission. In this dissertation, I will demonstrate technology advancement of instruments in this frequency regime with new characterization techniques, machining strategies, and scientific models of the spectral behavior of gas species targeted by these instruments.
I begin this work with a description of radiation pattern measurements and their use in astronomical instrument characterization. I will introduce a novel technique to measure complex (phase-sensitive) field patterns using direct detectors. I successfully demonstrate the technique with a single pixel microwave inductance detectors (MKID) experiment. I expand that work by measuring the APEX MKID (A-MKID) focal plane array of 880 pixel detectors centered at 350 GHz. In both chapters I discuss the development of an analysis pipeline to take advantage of all information provided by complex field mapping. I then discuss the design, simulation, fabrication processes, and characterization of a circular-to-rectangular waveguide transformer module integrated into a circularly symmetric feedhorn block. I conclude with a summary of this work and how to advance these technologies for future ISM studies.
I begin this work with a description of radiation pattern measurements and their use in astronomical instrument characterization. I will introduce a novel technique to measure complex (phase-sensitive) field patterns using direct detectors. I successfully demonstrate the technique with a single pixel microwave inductance detectors (MKID) experiment. I expand that work by measuring the APEX MKID (A-MKID) focal plane array of 880 pixel detectors centered at 350 GHz. In both chapters I discuss the development of an analysis pipeline to take advantage of all information provided by complex field mapping. I then discuss the design, simulation, fabrication processes, and characterization of a circular-to-rectangular waveguide transformer module integrated into a circularly symmetric feedhorn block. I conclude with a summary of this work and how to advance these technologies for future ISM studies.
ContributorsDavis, Kristina (Author) / Groppi, Christopher E (Thesis advisor) / Bowman, Judd (Committee member) / Mauskopf, Philip (Committee member) / Jellema, Willem (Committee member) / Pan, George (Committee member) / Trichopoulos, Georgios (Committee member) / Arizona State University (Publisher)
Created2018
Description
Studying the interstellar medium (ISM) is the key to answering questions about how material that exists between the stars drives the evolution of galaxies. Current models for the ISM life-cycle exist, but several steps lack observational evidence. Inthis dissertation I present the work I completed in support of up-coming mission to further study the ISM. This work includes ancillary data analysis of the Carina Nebula for the upcoming balloon mission: astrophysics stratospheric telescope for
high spectral resolution observations at submillimeter wavelengths (ASTHROS). I present a derived molecular gas map of Carina from Herschel dust continuum emission maps at wavelengths between 70-500 microns. I compare it to the distribution
of atomic gas, using HI 21 cm data, and of multiple CO isotopologues for the J = 1 → 0 rotational transition. I use these data sets to separate the CO–dark and CO–bright molecular components to study their relative contribution to the total molecular gas mass budget in Carina. I studied the transition between atomic and molecular gas in this region, by deriving the molecular fraction as a function of position, and comparing it to theoretical models of this transition. I also present the flight hardware design, testing, and space qualification of the intermediate frequency (IF) harness for the galactic/extragalactic ultra long duration balloon spectroscopic terahertz observatory (GUSTO). The harness transmits signal via novel cryogenic flexible stripline based transmission lines operating from 0.3 - 6.0 GHz. I designed three sets of 8-channel ribbons with characteristic insertion loss of 3.07 dB/ft at 5 GHz while the line was at a temperature gradient between 20 K - 300 K. Missions like GUSTO make use of non-linear mixing elements to achieve down-conversion of higher frequencies into IF bands. The mixers have a temperature dependent impedance that is difficult to measure. The last chapters of this work detail my attempt to carry out in-situ vacuum cryogenic calibrations using industry standard commercial off-the-shelf calibration kits and cryogenic RF electro-mechanical latching switches. I present the complex impedance of a non-linear superconducting transmission line as measured with a cryogenic calibration.
ContributorsNeric, Marko (Author) / Groppi, Chris (Thesis advisor) / Mauskopf, Philip (Committee member) / Scowen, Paul (Committee member) / Trichopoulos, Georgios (Committee member) / Jacobs, Daniel (Committee member) / Arizona State University (Publisher)
Created2023
Description
Millimeter astronomy unlocks a window to the earliest produced light in the universe, called the Cosmic Microwave Background (CMB). Through analysis of the CMB, overarching features about the universe's evolution and structure can be better understood. Modern millimeter-wave instruments are constantly seeking improvements to sensitivity in the effort to further constrain small CMB anisotropies in both temperature and polarization. As a result, detailed investigations into lesser-known processes of the universe are now becoming possible.
Here I present work on the millimeter-wavelength analysis of z ≈ 1 quiescent galaxy samples, whose conspicuous quenching of star formation is likely the result of active galactic nuclei (AGN) accretion onto supermassive black holes. Such AGN feedback would heat up a galaxy's surrounding circumgalactic medium (CGM). Obscured by signal from cold dust, I isolate the thermal Sunyaev-Zel'dovich effect, a CMB temperature anisotropy produced by hot ionized gas, to measure the CGM's average thermal energy and differentiate between AGN accretion models. I find a median thermal energy that best corresponds with moderate to high levels of AGN feedback. In addition, the radial profile of cold dust associated with the galaxy samples appears to be consistent with large-scale clustering of the universe.
In the endeavor of increasingly efficient millimeter-wave detectors, I also describe the design process for novel multichroic dual-polarization antennas. Paired with extended hemispherical lenslets, simulations of these superconducting antennas show the potential to match or exceed performance compared to similar designs already in use. A prototype detector array, with dual-bowtie and hybrid trapezoidal antennas coupled to microwave kinetic inductance detectors (MKIDs) has been made and is under preparation to be tested in the near future.
Finally, I also present my contributions to the cryogenic readout design of the Ali CMB Polarization Telescope (AliCPT), a large-scale CMB telescope geared towards searching the Northern Hemisphere sky for a unique `B-mode' polarization expected to be produced by primordial gravitational waves. Cryogenic readout is responsible for successful interfacing between room temperature electronics and sensitive detectors operating on AliCPT's sub-Kelvin temperature focal plane. The development of millimeter-wave instruments and future endeavors show great potential for the overall scientific community.
ContributorsMeinke, Jeremy (Author) / Mauskopf, Philip (Thesis advisor) / Alarcon, Ricardo (Committee member) / Scannapieco, Evan (Committee member) / Trichopoulos, Georgios (Committee member) / Arizona State University (Publisher)
Created2023
Description
Kinetic Inductance Detectors (KIDs) offer highly sensitive solutions for millimeter and submillimeter wave astronomy. KIDs are superconducting detectors capable of measuring photon energy and arrival time. KIDs use the change in surface impedance of the superconductor when an incident photon is absorbed and breaks Cooper pairs in the superconducting material. This occurs when KIDs use a superconducting resonator: when a photon is incident on the inductor, the photon is absorbed and inductance increases and the resonant frequency decreases. The resonator is weakly coupled to a transmission line which naturally allows for multiplexing to allow up to thousands of detectors to be read out on one transmission line. In this thesis a KID is presented to be used at submillimeter wavelengths. I optimized a polarization-sensitive aluminum absorber for future Balloon-borne Large Aperture Submillimeter Telescope (BLAST) missions. BLAST is designed to investigate polarized interstellar dust and the role of magnetic fields on star formation. As part of the effort to develop aluminum KIDs for BLAST, I investigated the optical coupling method including different feedhorn structures and a hybrid design. I present a suite of simulations calculating the absorption efficiency of the absorber. The optimized KID is a feedhorn/waveguide coupled front-illuminated detector that achieves 70% absorption over the frequency band centered at 250um.
ContributorsChamberlin, Kathryn (Author) / Mauskopf, Philip (Thesis advisor) / Trichopoulos, Georgios (Committee member) / Zeinolabedinzadeh, Saeed (Committee member) / Arizona State University (Publisher)
Created2022
Description
This dissertation presents a comprehensive study on the advancement of astrophysical radio, microwave, and terahertz instrumentation/simulations with three pivotal components.First, theoretical simulations of high metallicity galaxies are conducted using the supercomputing resources of Purdue University and NASA. These simulations model the evolution
of a gaseous cloud akin to a nascent galaxy, incorporating variables such as kinetic energy,
mass, radiation fields, magnetic fields, and turbulence. The objective is to scrutinize the
spatial distribution of various isotopic elements in galaxies with unusually high metallicities and measure the effects of magnetic fields on their structural distribution.
Next, I proceed with an investigation of the technology used for reading out Microwave Kinetic Inductance Detectors (MKIDs) and their dynamic range limitations tied to the current
method of FPGA-based readout firmware. In response, I introduce an innovative algorithm
that employs PID controllers and phase-locked loops for tracking the natural frequencies
of resonator pixels, thereby eliminating the need for costly mid-observation frequency recalibrations which currently hinder the widespread use of MKID arrays.
Finally, I unveil the novel Spectroscopic Lock-in Firmware (SpLiF) algorithm designed to
address the pernicious low-frequency noise plaguing emergent quantum-limited detection
technologies. The SpLiF algorithm harmonizes the mathematical principles of lock-in amplification with the capabilities of a Fast Fourier Transform to protect spectral information
from pink noise and other low-frequency noise contributors inherent to most detection systems. The efficacy of the SpLiF algorithm is substantiated through rigorous mathematical
formulation, software simulations, firmware simulations, and benchtop lab results.
ContributorsHoh, Jonathan (Author) / Groppi, Christopher E (Thesis advisor) / Jamison-Hooks, Tracee (Committee member) / Buie II, Edward (Committee member) / Trichopoulos, Georgios (Committee member) / Scannapieco, Evan (Committee member) / Arizona State University (Publisher)
Created2024