Laser trapping of francium for the electron Electric-Dipole-Moment search

We prepared for the precise spectroscopy of Francium (Fr) for search of the electron electric dipole moment at CYRIC, Tohoku University. Fr is produced by the fusion reaction by ¹⁸O supplied from by the cyclotron accelerator and ¹⁹⁷Au as a target. Fr atoms are cooled and trapped by the laser cooling technique in a magneto-optical trap (MOT). Then the trapped Fr in MOT will be transferred to an optical lattice system placed between electrodes for high-voltage apply. The spin precession of Fr atoms will be measured with the Ramsey fringe method.  We have been promoting the development of the Fr producing part with ¹⁸O beam, and the laser cooling and trapping part using stable Rb atoms as offline experiments simultaneously. In this system, Fr trapping in MOT is a key component to link these systems and finalize preparations for the measurement. We found a sign of trapped atom in MOT in 2017 and proceed further trap experiments to observe obvious fluorescence from trapped atoms. Recent progress of this experiment will be reported.