Measurements of Distributions of Ba Atom Density and Electrode Temperature in Low-pressure Fluorescent Lamp

The lifetime of a fluorescent lamp mainly depends on the loss of Ba atoms from its electrode, i.e. the rate of Ba atoms loss controls the lifetime of the lamp. The mechanism of the loss has not been clarified yet sufficiently. We have investigated relationship between electrode temperature distributions and characteristics of Ba atom emission in a fluorescent lamp which are measured by using black-body radiation method and laser-induced fluorescence (LIF) method, respectively. The lamp was operated at AC 100V-60 Hz. The experimental results of electrode temperature measurement are consistent with our previous report that the lifetime of the lamp depends on thermal evaporation from a hot spot at an anode half-cycle.