English: Physicist Irving Langmuir (center) in his lab at General Electric in 1922, showing radio pioneer Guglielmo Marconi (right) a new 20 kW triode vacuum tube GE has developed for radio transmitters. Langmuir, a pioneer in vacuum technology and the inventor of the diffusion pump, is responsible for developing the modern "hard vacuum" radio tubes. The man on the left is Willis R. Whitney, director of GE's research lab.