Trapping radioactive atoms for basic and applied research

We report on the trapping of radioactive atoms for a variety of nuclear, atomic, and applied physics investigations. To date we have trapped 5 different radioisotopes of rubidium and cesium (^82–84Rb+^135,137Cs) using a magneto-optical trap (MOT) coupled to a mass separator. By optimizing the efficiency of this system, we have been able to trap as many as 6 million radioactive atoms and detect as few as 100. This technology is being applied in three different areas: (1) the parity-violating, β-decay asymmetry measurement of polarized ⁸²Rb; (2) the study of ultracold fermionic ⁸⁴Rb atoms; and (3) the use of MOTs for the ultrasensitive detection of selected radioactive species. Although all of these projects are in a formative stage of development, we highlight the progress that we have made in: (1) the trapping of ⁸²Rb atoms in double MOT system; (2) the hyperfine structure measurement of the 5P_1/2 and 5P_3/2 levels in ⁸²Rb; (3) the simultaneous trapping of ⁸⁴Rb and ⁸⁷Rb in overlapping MOTs; and (4) the first trapping and isotopic ratio measurement of ¹³⁵Cs and ¹³⁷Cs in a MOT. This revised version was published online in August 2006 with corrections to the Cover Date.