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.
While the original goal to develop receiver technologies has been accomplished, the path to this accomplishment required a far more holistic approach than originally anticipated. The goal of the present work has expended exponentially from that of KAPPas promised technical achievements. In the present work, KAPPa and its extension, I present solutions ranging from 1) the creation of large scale astronomical maps, 2) metaheuristic algorithms that solve tasks too complex for humans, and 3) detailed technical assembly of microscopic circuit components. Each part is equally integral for the realization of a ~1000 pixel THz arrays.
Our automated tuning algorithm, Alice, uses differential evolution techniques and has been extremely successful in its implementation. Alice provides good results for characterizing the extremely complex tuning topology of THz receivers. More importantly, it has accomplished rapid optimization of an entire array without human intervention. In the age of big data astronomy, I have prepared THz heterodyne receiver arrays by making cutting edge community-oriented data analysis tools for the future of large-scale discovery. I present a from-scratch reduction and analysis architecture developed for observations of 100s of square degree on-the-sky maps with SuperCam to address the gulf between observing with single dish antennas versus a truly integrated focal plane array.
The interaction of the 21 cm hyperfine ground state emission/absorption-line of HI with the cosmic microwave background (CMB) and the radiation from the first luminous sources in the universe can be used to extract cosmological information about the EoR. Theorists have created global redshifted 21 cm EoR models of this interaction that predict the temperature perturbations to the CMB in the form of a sky-averaged difference temperature, Tb. The difficulty in measuring Tb is that it is
predicted to be on the order of 20 to 100 mK, while the sky foreground is dominated
by synchrotron radiation that is 105 times brighter. The challenge is to subtract the much brighter foreground radiation without subtracting the Tb signal and can only be done when the data has small error levels.
The Experiment to Detect the Global EoR Signature (EDGES) is an effort to measure Tb with a single wide field-of-view well-calibrated antenna. This dissertation focuses on reducing systematic errors by quantifying the impact of the chromatic nature of the antenna’s beam directivity and by measuring the variability of the spectral index of the radio sky foreground. The chromatic beam study quantified the superior qualities of the rectangular blade-shaped antenna and led to its adoption over the previously used fourpoint-shaped antenna and determined that a 5 term polynomial was optimum for removing the foreground. The spectral index, β, of the sky was measured, using 211 nights of data, to be −2.60 > β > −2.62 in lower LST regions, increasing to −2.50 near the Galactic plane. This matched simulated results using the Guzm´an et al. (2011) sky map (∆β < 0.05) and demonstrated the exceptional stability of the EDGES instrument. Lastly, an EoR model by Kaurov & Gnedin (2016) was shown to be inconsistent with measured EDGES data at a significance level of 1.9.
Undersea scientific ocean exploration and research only began in earnest approximately150 years ago. Much has been learned and discovered in that time, but there are also gaps in understanding of the ocean depths. One source of the knowledge gap is the relative lack of crewed exploration in some regions of the ocean. This work presents a vehicle that provides divers with longer time at deeper depths than is currently available in an unpressurized environment, reduces diver workload, and improves situational awareness. Working in collaboration with the scientific diver community, top-level requirements were defined, and a Concept of Operations was developed. This effort is followed up with a vehicle design which provides the capability for two divers to complete unpressurized dives to 200 meters, remain there for 20 minutes, and return to the surface within 12 hours. Additional functionality provided by the vehicle includes significant cargo capacity, voice and data communication with the surface, geolocation capabilities, and automated maneuvering and decompression management. Analysis of the hull shape and propulsion system is presented which demonstrates that the vehicle can reach its velocity and acceleration performance requirements. A virtual environment is then presented which has the potential to allow for end-to-end mission performance evaluation. Finally, the constraints on the life support system are discussed and source code for a simulation is presented. The final chapter of this work examines a hypothetical mission to 200 meters depth. The various phases of the mission are discussed as well as the potential consumption of both oxygen and electricity. Two life support gas mixtures are examined, and the resulting decompression profiles are presented. The final analysis shows that it is possible to conduct dives to 200 meters, perform 20 minutes of work, and return to the surface within 12 hours using the CUTLASS vehicle that is presented.