A proposed method of efficient laser trapping of neutral radium atoms

We report theoretical studies of an efficient accumulation of Ra-225 atoms in a magneto-optical trap (MOT) from an atomic beam. The number of atoms in the trap is limited due to the large leakage into metastable D states from the cooling transition and the loss mechanism from collisions with the background gases and with other elements in the atomic beam. We propose a setup consisting of an efficient Zeeman slower, an optical atomic beam deflector, and an Egg-MOT, which provides a large capture velocity, e.g. the Zeeman slower capture velocity of 581 ms(-1) and the MOT capture velocity of 46 ms(-1). Furthermore, the pure slow atomic beam produced by the optical atomic beam deflector can maximize the number of trapped atoms and their lifetime in a ultra high vacuum chamber by minimizing the collisional loss. Our proposed setup allows for the search for a permanent electric dipole moment based on laser-cooled and trapped radium atoms with improved sensitivity.This work was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Rare Isotope Science Project of Institute for Basic Science (2013M7A1A1075765)