Design and Construction of an Electron Electric Dipole Moment Experiment Using Thorium Monoxide*

Observation of an electron electric dipole moment (eEDM) would imply new sources of CP violation beyond the Standard Model. By measuring spin precession signals on a cryogenic molecular beam, the ACME collaboration is searching for the eEDM in the metastable H $^3\Delta_1$ state of thorium monoxide. We discuss the design and completed assembly of the first generation of this experiment. Precise electric and magnetic field sources, magnetic shields, and a fluorescence collection system have been constructed and installed, and the molecule beam source has been optimized.\footnote{N.R.~Hutzler \textit{et al.}, Phys. Chem. Chem. Phys., 13, 18976-18985 (2011)} With this system we have begun collecting and analyzing eEDM data.