The Yale Undergraduate Research Journal


The Simons Observatory (SO) is a new cosmic microwave background (CMB) experiment consisting of four telescopes. SO is being constructed at an elevation of 5,190 meters on Cerro Toco in the Atacama Desert in Chile, and is set to begin observation in 2022. SO will employ 60,000 detectors, yielding a sensitivity greater than all previous CMB experiments. To achieve low noise performance the telescope cryostats will be cooled to ~100 mK using low temperature dilution refrigerators. Measuring cryostat temperatures is essential for pre-deployment testing, telescope installation, and telescope monitoring during observation. The purpose of this project is to design, build, and test the hardware necessary for regular measurements at all temperature stages of the SO telescopes. This paper details my design of housekeeping hardware, contribution to temperature sensor calibration, and characterization of calibration discrepancies attributable to faults within my lab’s dilution refrigerator.