UC San Diego

The Simons Array, located in the Atacama Desert in northern Chile, is a project designed to measure the polarization of the cosmic microwave background (CMB). Studying the CMB in this capacity provides insight into the history of our Universe and contributes to the understanding of its current evolution. The POLARBEAR-2b receiver is the second cryogenic receiver designed and built for the Simons Array. This instrument houses over 7,000 transition-edge sensor bolometers cooled to a base temperature of 250 millikelvin that are read out with a digital frequency multiplexing scheme that minimizes the internal wiring. The signals are amplified using superconducting quantum interference devices that are cooled to 4 Kelvin. The optical components of this receiver include a ultra-high molecular weight polyethelyne window, a cryogenic, continuously rotating half-wave plate, an infrared-blocking filter, and three reimaging alumina lenses with a lyot aperture. Careful assembly methods of all the elements mentioned to build the receiver are necessary to ensure successful operation of the instrument during in-lab testing and in the field. POLARBEAR-2b was integrated at UC San Diego before it began its deployment in January 2020 and was hoisted onto the Paul Simons telescope in July of 2022. This dissertation focuses on the final in-lab integration testing and results as well as the receiver assembly methods and modifications that enabled a successful field deployment of the POLARBEAR-2b receiver.