129Xe EDM Search Experiment Using Active Nuclear Spin Maser

An active nuclear spin maser, which enables a precision measurement of spin precession frequency, is employed in the experimental search for permanent electric dipole moment (EDM) in the diamagnetic atom 129 Xe.In order to eliminate systematic errors which limit the sensitivity of the experiment to an EDM, the following tactics are adopted: (i) 3 He comagnetometry for the cancellation of long-term drifts in the external magnetic fields and (ii) double-cell geometry for the mitigation of frequency shifts due to interaction of 129 Xe spin with polarized Rb atoms.In the present work, the design for the double-cell has been changed and a magnetic shield-coil system to provide a highly homogeneous magnetic field has been newly introduced.Thanks to increased polarization and longer 3 He spin relaxation time, the dual-species maser of 129 Xe and 3 He in a double-cell geometry operated successfully.Our experiment is now at the stage of assembling these separate technical elements in order to start the measurement of 129 Xe EDM in the 10 -28 ecm region.