OPTICAL-PUMPING OF METASTABLE MAGNESIUM IN AN ATOMIC-BEAM

A selective depopulation of the metastable (MgP1)-P-3 level is obtaine d in an atomic beam by optical pumping with the P-3(1)-3D multiplet tr ansition at 383.2 nm. The advantage of such a pumping for the Mg frequ ency standard at 601 GHz is discussed. This pumping scheme results mor e effective than the alternative one, which makes use of the 517 nm P- 3(1)-S-3(1) transition. In particular an increase of the stability of the Mg clock by about one order of magnitude is foreseen.