Progress on the laser manipulation of radioactive atoms for precision studies of the weak interaction

The authors report the recent progress on laser manipulation of the short-lived (22 sec half-life) radioactive 21Na atoms. Since they successfully demonstrated laser trapping of short-lived radioactive isotope at LBL's 88 inch Cyclotron, the authors have made substantial improvements in their experimental apparatus. Using a new high temperature oven and MgO target, the thermal atomic beam of 21Na has been greatly increased. A new trapping magnet has been fabricated, which promises higher trapping efficiency. Currently they are working on the precise measurement of the hyperfine structure of the 21Na and new laser trapping schemes which provide polarized trapped atoms. These techniques will lead to a precision measurement of the decay asymmetry parameter, which is a sensitive test of the V-A structure of the weak charged current