The effect of discharge mode on Ba atom loss from the electrode ofa low-pressure fluorescent lamp

摘要

The loss of Ba atoms from the electrode of a fluorescent lamp was measured while the lamp wasrnoperated under glow and arc discharge modes at 60 Hz using a laser-induced fluorescence (LIF)rntechnique. The temporal and spatial distribution of Ba atoms was found to be completely differentrnin the two discharge modes. At the arc discharge mode, the Ba atom density had two peaks in itsrntemporal distribution, and was about twofold larger in the anode half-cycle than that in the cathodernhalf-cycle. At the glow discharge, the Ba atom density in the anode half-cycle was negligiblerncompared with that in the cathode half-cycle. Spatially; at the arc discharge mode, Ba atoms werernfound to be emitted mainly from the hot spot of the electrode. At the glow discharge mode, Ba atomsrnwere found to be sputtered from all parts of the electrode homogeneously. The mechanism of Barnatom loss from the electrode in both modes was discussed.