LASER DECELERATION AND TRAPPING OF METASTABLE HELIUM-ATOMS

Metastable helium atoms with an initial velocity of 1000 m/s are decel erated using the Zeeman slowing method. A magnetooptical trap operatin g in a novel regime with large laser detuning (delta = -25 Gamma) is l oaded with 3 x 10(7) atoms at a temperature of 2 mK. The volume of tra pped atoms is large (similar to 0.1 cm(3)) and atoms predominantly int eract with light at the edges of the trapping volume. This situation i s favourable to minimise trap losses by light-induced Penning ionisati on. The trap lifetime is 0.8 s. The number of trapped atoms is more th an two orders of magnitude larger than previously obtained for metasta ble helium. The feasibility to use this trap as a first stage to reach the Bose-Einstein-Condensation regime is discussed.