Kinetic inductance detectors (KIDs) are superconducting thin-film microresonators that are sensitive photon detectors. These detectors are a candidate for the next generation of experiments designed to measure the polarization of the cosmic microwave background (CMB). I discuss the basic theory needed to understand the response of a KID to light, focusing on the dynamics of the quasiparticle system. I derive an equation that describes the dynamics of the quasiparticle number, solve it in a simplified form not previously published, and show that it can describe the dynamic response of a detector. Magnetic flux vortices in a superconducting thin film can be a significant source of dissipation, and I demonstrate some techniques to prevent their formation. Based on the presented theory, I derive a corrected version of a widely-used equation for the quasiparticle recombination noise in a KID. I show that a KID consisting of a lumped-element resonator can be sensitive enough to be limited by photon noise, which is the fundamental limit for photometry, at a level of optical loading below levels in ground-based CMB experiments. Finally, I describe an ongoing project to develop multichroic KID pixels that are each sensitive to two linear polarization states in two spectral bands, intended for the next generation of CMB experiments. I show that a prototype 23-pixel array can detect millimeter-wave light, and present characterization measurements of the detectors.

This thesis presents the development of kinetic inductance detectors (KIDs) for cosmic microwave background (CMB) polarimetry. Increasingly precise measurements of the CMB have led to much of our understanding of the observable universe; future measurements of the CMB will require the development of new detectors as progressively fainter signals are targeted. In particular, a measurement of the primordial B-mode polarization signal, which would offer strong evidence of inflation, will require at least a 50 times increase in detector count. KIDs are an attractive detector option for next-generation CMB experiments due to their low-noise and high-multiplexing factor. In this thesis, I present KIDs optimized for ground-based CMB observations, which are sensitive to a 150 GHz spectral band where the CMB spectrum peaks. This research demonstrates the first systematic studies of lumped-element KIDs (LEKIDs) optimized for CMB surveys and shows the readiness of the detectors for on-sky observations. First, I present the design and performance of horn-coupled LEKIDs, which are sensitive to a single polarization. I show that KIDs can meet the stringent noise and sensitivity requirements necessary for a competitive CMB detector. Second, I present a novel method for reducing crosstalk between LEKIDs, which is important for controlling instrument systematics. Third, I present the design and performance of dual-polarization LEKIDs, which are sensitive to orthogonal polarizations within a single spectral band and double the number of detectors per array, increasing the sensitivity. Finally, I present the initial analysis of millimeter-wave observations of a nearby galaxy cluster, Abell 2443, taken with the LEKID-based NIKA2 instrument on the IRAM 30 m telescope. This is part of ongoing research to make high-resolution measurements of the Sunyaev–Zel'dovich effect, seen as a distortion in the CMB spectrum.

Cosmic microwave background observations have been fundamental in forming the standard model of cosmology. Ongoing and upcoming cosmic microwave background experiments aim to confirm this model and push the boundaries of our knowledge to the very first moments of the Universe. Non-cosmological microwave radiation from the Galaxy and beyond, called foregrounds, obscures and contaminates these measurements. Understanding the sources and effects of foregrounds and removing their imprint in cosmic microwave background observations is a major obstacle to making cosmological inferences. This thesis contains my work studying these foregrounds. First, I will present observations of a well-known but poorly understood foreground called anomalous microwave emission. Second, I will present results forecasting the capability of a next-generation satellite experiment to detect cosmic microwave background spectral distortions in the presence of foregrounds. Third, I will present results studying the effect of foregrounds on the cosmic microwave background self-calibration method, which allows experiments to calibrate the telescope polarization angle using the cosmic microwave background itself. Fourth, I will present my analysis characterizing the performance of and producing maps for the E and B Experiment. Fifth, I will present my research contributions to the readout system that used in the laboratory to operate kinetic inductance detectors, which are being developed for cosmic microwave background observations. Lastly, I will conclude with future prospects in the field of foregrounds and cosmic microwave background cosmology.

No description available.

No description available.

The Sunyaev Zel'dovich effect (SZE) is a secondary distortion of the cosmic microwave background (CMB) spectrum produced by galaxy clusters that allows for measurements of intra-cluster gas properties. Current experiments are using large arrays of multiplexed transition-edge sensor bolometers to achieve the sensitivities required for SZE cluster surveys and targeted cluster SZE observations. This thesis describes the APEX-SZ experiment, the first instrument to produce scientific results from observations with such an array. The scientific motivation for the APEX-SZ experiment is discussed, followed by a description of the APEX-SZ experiment and frequency domain multiplexing technologies. We have developed a custom data reduction pipeline for the experiment which uses a variety of filters, both in the temporal and spatial domain to produce 1' resolution maps of the SZE at 150GHz. The results of data analysis for the Bullet cluster (lE0657-56) and Abell 2204 (A2204) are presented. Both clusters are assumed to be isothermal and in hydrostatic equilibrium, allowing a fit to an isothermal beta-model and subsequent mass fraction estimates. The maximum likelihood parameters and constant likelihood 68% confidence intervals are estimated using a Markov-Chain Monte Carlo method to sample the beta-model parameter space. We measure cluster gas mass fractions with r 2500 to be 0.140 +/- 0.035 and 0.058 +/- 0.035 for the Bullet cluster and A2204 respectively. The Bullet gas mass fraction is consistent with previous results from X-ray analysis. The gas mass fraction for A2204 does not agree well with other A2204 observations, however the large scatter in the gas mass fractions determined from previous X-ray and SZE analyses indicates that a more complex density model may be appropriate for this cluster.

The universe is a complex environment playing host to a plethora of macroscopic and microscopic processes. Understanding the interplay and evolution of such processes will help to shed light on the properties and evolution of the universe. The juxtaposition is that in order to study small scale effects one needs to observe large scale structure as the latter objects trace the history of our universe. Galaxy groups and clusters are the largest known objects in the universe and thus provide a means to probe the evolution of structure formation in the universe as well as the underlying cosmology. In this thesis we investigate how clusters observed through the Sunyaev-Zel’dovich (SZ) effect can be used to constrain cosmological models. In addition, we present the first results of the Atacama Cosmology Telescope (ACT), a mm-wave telescope measuring the small-scale microwave background anisotropy, and conclude with preliminary SZ cluster detection performed on the latest ACT sky maps. In the first part of this thesis we investigate the ability of high resolution cosmic microwave background (CMB) experiments to detect hot gas in the outer regions of nearby group halos. We construct two hot gas models for the halos; a simpler adiabatic formalism with the gas described by a polytropic equation of state, and a more general gas description which incorporates feedback effects in line with constraints from X-ray observations. We calculate the thermal Sunyaev- Zel’dovich (tSZ) signal in these halos and compare it to the sensitivities of upcoming and current tSZ survey experiments such as ACT, PLANCK and the South Pole Telescope (SPT). Through the application of a multi-frequency Wiener filter, we derive mass and redshift based tSZ detectability limits for the various experiments, incorporating effects of galactic and extragalactic foregrounds as well as the CMB. In this study we find that galaxy group halos with virial masses below 1014M. can be detected at z ~< 0.05 with the mass limit dropping to 3 − 4 × 1013M. at z ~< 0.01. Probing such halos with the tSZ effect allows one to map the hot gas in the outer regions, providing a means to constrain gas processes, such as feedback, as well as the distribution of baryons in the local universe. In the fourth chapter, we extend this analysis and determine the ability of ACT to constrain galactic feedback and star formation in clusters and groups using the tSZ effect. We present a new microwave deblender, which provides a means of extracting accurate halo fluxes and radial profiles from maps of the tSZ effect. Considering various surveys that could be performed by ACT, we use multi-frequency filtering on simulated sky maps to predict how well such surveys will constrain gas properties using a Fisher matrix analysis. We find that the current ACT survey will be unable to constrain any gas parameters. However, if ACT were to survey a smaller area then we will be able to constrain feedback. Furthermore, with greater sensitivity, we will be able to place interesting constraints on the gas feedback, and baryon and stellar fractions. The fifth chapter in this thesis concerns itself with the first results of the Atacama Cosmology Telescope Project. In this section we discuss the map-making method as well as telescope beam characterisation, an understanding of which is important in any subsequent map analyses. In addition, we present maps of eight clusters observed at 148 GHz via the SZ effect, and provide flux and signal to noise estimates of the clusters. In the final chapter we present a preliminary analysis of the latest 148 GHz ACT maps from the 2008 observing season. We study the sky maps using single frequency wiener filtering, allowing for CMB, dust and correlated noise contamination. To substantiate our results, we compare the number counts, recovered fluxes and sample purity from simulated sky maps. The compounding effects of CMB and correlated noise result in high contamination levels below a signal to noise ratio of 6, however our investigation shows that above 8¾ our cluster sample is ¼ 80% pure. A cluster list containing 44 detections, of which 8 are previously known, is also presented, along with a Table listing the candidate cluster positions and fluxes. The candidate cluster catalogue will be used for follow-up studies using optical and X-ray observations. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

Thesis (Ph. D.)--University of Chicago, Dept. of Astronomy and Astrophysics, Jun. 2003. / Includes bibliographical references (p. 168-171). Also available on the Internet.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, June 2003. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 93-98).