Advanced Optical Instrumentation for the Simons Observatory Large Aperture Telescope

• Main Author: Kofman, Anna, Marina
• Other Authors: Devlin, Mark, J
• Format: Thesis
• Language: English
• Published: 2024
• Subjects: Astrophysics and Astronomy; Physics; Astronomy; Cosmic Microwave Background; Cosmology; Cryogenic; Instrumentation; Telescope; South pole
• Online Access: https://repository.upenn.edu/handle/20.500.14332/60036; https://hdl.handle.net/20.500.14332/60036

2024 For over 60 years, scientists have been studying the oldest observable light in our universe, the Cosmic Microwave Background (CMB), in order to probe the evolutionary history of our universe and develop its defining fundamental model. To observe this relic radiation, instrument teams have developed space-based and ground-based telescopes capable of mapping the microwave sky down to arc-minute scales, including experiments such as Planck, the Atacama Cosmology Telescope (ACT), and the South Pole Telescope (SPT). However, more sensitive instruments are needed to further rule out competing evolutionary models and place tighter constraints on cosmological parameters such as the primordial baryon density, the Hubble constant, and the growth of structure in our universe. In response to the call for higher sensitivity measurements of the millimeter sky, the Simons Observatory (SO) has developed a Large Aperture Telescope (LAT) and three Small Aperture Telescopes (SAT) to study the CMB from the Chilean Andes. The LAT houses the 2.4 m diameter Large Aperture Telescope Receiver (LATR), the largest cryogenic receiver built for studying the CMB to-date. The LATR will house over 62,000 Transition Edge Sensor (TES) detectors operating at 100 mK and sensitive to frequencies between 27 GHz and 280 GHz. These detectors, and the supporting optical and readout components, will live inside of 13 Optics Tubes (OT) in the receiver. In order to achieve the sensitivity requirements set by the SO science team, nearly a decade of research, design and testing work went into developing the telescope and its receiver. This thesis will present the motivations behind the mechanical, optical, cryogenic, readout and shielding designs for the LATR and OTs. In particular, this thesis will focus on the work surrounding the development, final design, and testing of the Optics Tubes and their integration into the receiver. PhD