Production of an Intense Atomic Beam of Barium in Metastable States

A device for producing an intense atomic beam of barium in metastable states has been developed. The population density of the states is measured by the resonance fluorescence method. The atoms are excited by an electric discharge in such a way that the atomic beam traverses the discharge plasma. The cross-section for excitation of barium by electron collisions is assumed to be as large as that for cesium. The efficiency of metastable atom production is estimated to be about 70%, and an atom flux of 4×1015 sec−1 cm−2 is obtained. The device is useful in forming a photoionized barium plasma using ordinary light sources.