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Here we present our progress on the JILA Generation III apparatus designed to measure the electron electric dipole moment (eEDM) in ThF⁺. The eEDM-sensitive ground electronic state in ThF⁺, immune to decoherence from spontaneous decay, provides an avenue to achieve a coherence time of ≈20 seconds [1,2]. Towards the measurement of the eEDM in ThF⁺, we review the proposed Gen. III multiplexed architecture and present a prototype apparatus designed to achieve a 20 s coherence time. A 20 s coherence time requires spatial homogeneity of the magnetic fields and suppression of black-body radiation. We discuss the successful implementation of a foam-insulated cryogenic system, and our work on the spatial homogeneity of our system’s magnetic fields.

[1] Gresh, Daniel N., et al. Journal of Molecular Spectroscopy 319 (2016): 1-9.

[2] Ng, Kia Boon, et al., arXiv:2202.01346 (2022)