Abstract: Tungsten-halogen lamps capable of satisfactory operation at relatively high temperatures exceeding 250° C. which comprise a high temperature glass or quartz envelope enclosing a tungsten filament and molybdenum, contain a fill comprising a mixture of noble gas, hydrogen, phosphorus, chlorine, and bromine. In a preferred embodiment the chlorine and bromine will be supplied by a single carbon atom hydrocarbon compound containing both halogens such as CHCl2Br and CH2BrCl.

Abstract: A long life tungsten halogen lamp comprising a fused silica envelope containing a coiled tungsten filament connected across inleads sealed therein which include inner portions of molybdenum wire. The molybdenum wire has been treated to increase its ductility and reduce the concentration of impurities at the surface. The fill gas at a room temperature total pressure of at least 2,000 torr comprises nitrogen, an inert gas and an iodine-bearing component which provides from 3.1 .times. 10.sup..sup.-7 to 9.6 .times. 10.sup..sup.-7 gram atoms of iodine per cubic centimeter of envelope volume.

Abstract: A long life tungsten halogen lamp comprising a fused silica envelope containing a coiled tungsten filament connected across inleads sealed therein which include inner portions of molybdenum wire. The molybdenum wire has been treated to increase its ductility and reduce the concentration of impurities at the surface. The fill gas at a room temperature total pressure of at least 2,000 torr comprises nitrogen, an inert gas and a bromine-bearing component which provides from 1.6 .times. 10.sup.-.sup.8 to 8.0 .times. 10.sup.-.sup.8 gram atoms of bromine per cubic centimeter of envelope volume.