Use of Thoriated-Tungsten Filaments in High-Power Transmitting Tubes

Experience gained in field and laboratory tests over the past ten years has shown that thoriated-tungsten filaments can be used in high-power transmitting tubes with life and reliability equal to that of the low-power types. This achievement can be attributed to improved materials such as oxygen-free high-conductivity copper and platinum-clad molybdenum, improved processing, and better exhaust facilities. Better appreciation of the mechanical problems and of the relationship between the carbide content, operating conditions, and life have all been important factors.