STUDIES OF WEAK INTERACTION EFFECTS BY LASER SPECTROSCOPY OF SHORT-LIVED ATOMS

Laser-induced nuclear orientation has been used to make sub-Doppler-resolution measurements of a nuclear isomer Rb-85m that has a lifetime of only a microsecond. The technique succeeds because the sampled atoms remove themselves before equilibrating. This paper describes two cases in which pre-equilibrium removal of atoms can prevent thermal equilibrium from obscuring information about the weak interaction that is present in the velocity profile of atoms as they recoil following beta decay. It should be possible to measure electron-antineutrino angular correlations in the beta decay of Kr-85, and to look for beta decay of tritium into an atomic bound state of He-3 - a fundamental effect predicted by weak interaction theory but never observed.