DESIGN AND THERMAL TESTING OF A CURRENT SUPPLY FOR CRYOSTAT: IN SEARCH OF AXIONS

Abstract

This thesis is part of an ongoing experimental effort aimed at detecting axions, a theoretical dark matter candidate, through their conversion to photons, which takes place in the presence of a magnetic field. The field is produced by a superconducting magnet, and the charging of a superconducting magnet presents several experimental challenges, such as the risk of thermal leaks and excessive heat loading of the system. This thesis designs and tests a scaled-down version of a larger experiment, including implementation and testing of phosphor bronze leads, carrying current from 300K (room temperature) to the 40K stage. We have calculated the optimal geometry for the phosphor bronze leads and built several custom parts to design, including an aluminum stand for the current leads. We then took thermal conductivity data over multiple cryostat cooldowns under various conditions. We successfully supplied 12.5A of current through the leads with a total heat load to the cold plate of approximately 1.5W, of which 0.5W is attributable to joule heating and 1W is attributable to passive thermal conduction along the leads.