Cryogenic and Magnet Design for the Princeton Axion Search

The Princeton aXion Search (PXS) is a new experiment to search for QCD axion dark matter in the 0.8-2.1 μeV mass range. PXS will consist of a resonator immersed in a ~5 Tesla field generated by a conduction cooled, Nb3Sn magnet of approximately 79cm bore and 102cm height. This talk describes the cryomechanical and magnet design for PXS. We outline the design of the cryostat, which is currently under construction and is set to be completed in the fall 2025. The cryostat consists of multiple pulse tube coolers dedicated to cooling the magnet system to 4K, as well as a pulse tube and dilution refrigerator for cooling the cavity and readout to roughly 40mK. We also present results from lab tests of a model magnet, roughly one-third the size of the full scale magnet. These tests are being used to validate the approach for magnet thermalization, quench protection, magnetic shielding, and cryogenic current supply up to 550A.