UC San Diego

The Simons Observatory is a cosmology polarization survey sited in the Atacama Desert in Chile at an altitude of 5200 m. The Simons Observatory has built one Large Aperture Telescope to survey small angular scale cosmology and three Small Aperture Telescopes to measure the large angular scale polarization of the Cosmic Microwave Background in search of primordial B-mode signals that would provide evidence of primordial gravitational waves theoretically created during inflation. The Small Aperture Telescopes are refractive, cryogenic telescopes that will each hold over 12,000 transition-edge sensor detectors to maximize sensitivity in measuring the tensor-to-scalar ratio, r. In this thesis, I discuss my work regarding the first-light Small Aperture Telescope built and validated at the University of California, San Diego, SAT-MF1. I discuss the design of the instrument, the integration and testing of the instrument in the San Diego lab, its deployment to Chile, and its commissioning before its initial science observation period. I will discuss various tests successfully validating the requirements of several SAT subsystems during its integration and testing period including: the cryogenics, structural support members, magnetic shielding, readout transmission, and platform vibration. I will discuss the models created to measure and estimate the instruments array yield and optical loading. Finally, I use these models to provide predictions of array yield improvements following instrument upgrades performed in early 2025.