Fill for high temperature tungsten-halogen lamps

1. Field of the Invention 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 CHClBr and CHBrCl.