254 nm Radiant Efficiency and Spectral Lines of High Output T6 Low Pressure Mercury Discharge Lamps with Neon-Argon Buffer Gases

摘要

The radiant efficiency of low pressure mercury (LPM) discharge lamps with outer diameter of 19 mm (T6) was measured for various parameters: cold spot temperature, discharge current, and buffer gas pressure. The buffer gas was neon (75%) and argon (25%) with total pressure 133-1333 Pa. The lamps were operated with cold spot temperatures 20-80℃ and discharge current 0.8-2.0 A. The electric field, input power, 254 nm radiant power and efficiency, spectra of Hg lines 254-579 nm and rare gas lines 738-850 nm in positive column were measured. It was shown that under discharge condition of cold spot temperature 45℃ and current 1.6 A, the 254 nm UV radiant efficiency had a maximum of above 40% for buffer gas pressure 133-267 Pa. The optimal mercury vapor pressure was approximate 1.2 Pa, corresponding to the cold spot temperature around 45℃. The sum of radiant energy percentage of other mercury lines and rare gas lines was less than 10%, which proved that high output LPM lamps can be good choice of UV radiation source.