Multichroic TES Bolometers and Galaxy Cluster Mass Scaling Relations
  with the South Pole Telescope
  The South Pole Telescope (SPT) is a high-resolution microwave-frequency
telescope designed to observe the Cosmic Microwave Background (CMB). To date,
two cameras have been installed on the SPT to conduct two surveys of the CMB,
the first in intensity only (SPT-SZ) and the second in intensity and
polarization (SPTpol). A third-generation polarization-sensitive camera is
currently in development (SPT-3G). This thesis describes work spanning all
three instruments on the SPT. I present my work in time-reversed order, to
follow the canonical narrative of instrument development, deployment, and
analysis. First, the development and testing of novel 3-band multichroic
Transition Edge Sensor (TES) bolometers for the SPT-3G experiment is detailed,
followed by the development and deployment of the frequency multiplexed
cryogenic readout electronics for the SPTpol experiment, and concluding with
the analysis of data taken by the SPT-SZ instrument. I describe the development
of a Bayesian likelihood based method I developed for measuring the integrated
Comptonization (Ysz) of galaxy clusters from the Sunyaev-Zel'dovich (SZ)
effect, and constraining galaxy cluster Ysz-mass scaling relations.
