Number 182 (Story #1), June 8, 1994 by Phillip F. Schewe and Ben Stein RADIOACTIVE ATOMS HAVE BEEN TRAPPED using a combination of laser beams and magnetic fields. Luis Orozco and his colleagues at Stony Brook produced rubidium-79 isotopes and sent them into a glass cell, where the atoms bounced back and forth between special non-stick walls until they rebounded slowly enough to become captured by the magneto-optical trap at the center of the cell. A Berkeley team led by Stuart Freedman slowed down a beam of sodium-21 atoms with lasers before the atoms entered the magneto-optical trap. In efforts to learn how to trap atoms efficiently, Michelle Stephens and Carl Wieman at the University of Colorado released stable cesium atoms into a cell, also with non-stick walls, and succeeded in holding 6% of the atoms at a time. The Colorado researchers predict that collection efficiencies can be as high as 50% for atoms in an optimal magneto-optical trap. The Stony Brook and Colorado groups are each interested in studying the phenomenon known as parity violation in radioactive isotopes, while the Berkeley group is interested in making precise measurements of beta decay. (G. Gwinner et al., Z-T. Lu et al., and M. Stephens et al., Physical Review Letters, 13 June 1994.)