Abstract

Discharge lamps with sodium alloys have been made in bulbs about 5 cm in diameter, a size chosen purposely small in order to attain readily the high current density required by the low vapor pressure of alloys. The most desirable elements, from the standpoint of both color and efficiency, proved to be cadmium and mercury in about equal proportions by weight with somewhat less than 10 percent sodium in solid solution with them. Such an alloy gave a white discharge, with good color values throughout the spectrum with the exception of reds, which were only fair. The overall efficiency was reduced by 30–40 percent, from 43 LPW for pure sodium to 25–30 LPW. Larger diameter bulbs would allow proportionately higher values. A reasonable maintenance was held for over 1000 hours. It could be improved by avoidance of the stem chamber, into which the alloy tends fractionally to diffuse.

© 1935 Optical Society of America

High Efficiency Mercury and Sodium Vapor Lamps*

L. J. Buttolph
J. Opt. Soc. Am. 29(3) 124-130 (1939)

Cadmium Magnesium Alloy Photo-Tubes

L. R. Koller and A. H. Taylor
J. Opt. Soc. Am. 25(6) 184-184 (1935)

Photometry and Energy Distribution of the High Intensity Mercury Lamp

L. B. Johnson
J. Opt. Soc. Am. 25(1) 36-38 (1935)

The Characteristics of the Sodium Lamp as Influenced by Vapor Pressure

Gorton R. Fonda and Andrew H. Young
J. Opt. Soc. Am. 24(2) 31-34 (1934)

Characteristics of Mercury Vapor–Metallic Iodide Arc Lamps

Gilbert H. Reiling
J. Opt. Soc. Am. 54(4) 532-540 (1964)