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  4. Measuring the Cosmic Microwave Background Radiation from Chile

Measuring the Cosmic Microwave Background Radiation from Chile

File(s)
Stevens_cornellgrad_0058F_12295.pdf (26.32 MB)
Permanent Link(s)
https://doi.org/10.7298/d13p-yx94
https://hdl.handle.net/1813/103248
Collections
Cornell Theses and Dissertations
Author
Stevens, Jason Roland
Abstract

Precise measurement of the cosmic microwave background (CMB) radiation holds the key to a surprising quantity of knowledge about cosmology and the early universe. Measurement of the power spectrum of the CMB yields information about inflation and gravitational waves in the early universe, the mass of the neutrino, and the number of effective neutrino species. As CMB photons pass through our universe, the interaction they have with its contents yield even more information. Scattering of the CMB photons off of the electrons in galaxy clusters can be used to extract the movement of those galaxy clusters, and gravitational lensing of the CMB photons tells the story of the evolution of massive structures in our universe. Extracting this information requires an extreme level of precision and care in the detection of these photons. This dissertation covers a number of subjects related to measuring CMB photons with telescopes in Chile. I first discuss the superconducting transition edge sensors used on some of these telescopes, and the testing and characterization of these sensors for the Simons Observatory. It is necessary to multiplex the detector signals to reduce thermal load on the cryostat cold stages, so I then discuss testing and characterization strategies for superconducting multiplexers. This begins with characterization of the time domain multiplexing chips used on Advanced ACTPol, and leads into characterization of microwave multiplexing chips like those that will be used in the Simons Observatory. Next, I present methods for designing and optimizing wide area CMB survey strategies from Chile, including the strategies that are used in Advanced ACTPol and the strategies that will be used in the Simons Observatory. I then describe recent results from the Atacama Cosmology Telescope that this work has contributed to. I conclude by summarizing the improvements we will see in measurements of the CMB from new observatories in the coming years.

Description
167 pages
Date Issued
2020-12
Keywords
Cosmic Microwave Background
•
Cosmology
•
Multiplexing
•
Observing Strategy
•
Survey Strategy
•
Transition Edge Sensors
Committee Chair
Niemack, Michael D.
Committee Member
Bean, Rachel E.
Nowack, Katja C.
Degree Discipline
Physics
Degree Name
Ph. D., Physics
Degree Level
Doctor of Philosophy
Rights
Attribution-NonCommercial 4.0 International
Rights URI
https://creativecommons.org/licenses/by-nc/4.0/
Type
dissertation or thesis
Link(s) to Catalog Record
https://newcatalog.library.cornell.edu/catalog/13312107

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