Efficient magneto-optical trapping of a metastable helium gasF. Pereira Dos Santos, F. Perales, J. Léonard, A. Sinatra, J. Wang, F. S. Pavone, E. Rasel, C. S. Unnikrishnan and M. LeducEur. Phys. J. AP, 14 1 (2001) 69-76DOI: https://doi.org/10.1051/epjap:2001140