New apparatus for magneto-optical trapping of francium

Summary form only given. We have constructed a new apparatus for on-line magneto-optical trapping of radioactive francium atoms at the Stony Brook Superconducting LINAC. An ion beam with an energy of /spl sim/100 MeV from the accelerator strikes a target of gold or isotopically enriched platinum mounted on the end of a tungsten rod. A heavy-ion fusion reaction [/sup 16,18/O(/sup 197/Au,xn) or /sup 19/F(/sup 198/Pt,xn)] selectively produces the isotopes /sup 208-212/Fr in the target room of the accelerator. The beam power and an auxiliary heater heat the target, allowing the francium to diffuse rapidly to the surface. The target ionizes the francium as it diffuses out. We then transport the francium as ions to a different room for subsequent neutralization and capture in a magneto-optical trap (MOT). Since the transport system is electrostatic, it is mass independent, allowing us to transport any isotope of Fr or even other alkalis. We have delivered over 3/spl times/10/sup 6/ Fr/sec to a Faraday cup in front of the trap, and tests show greater than 90% transport efficiency from the target. A small constriction in the vacuum system separates the target and transport region from the trap, permitting differential pumping of the trap.