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.