Delayed gassing in electron tubes

Various mechanisms have been studied experimentally to determine the causes of delayed gasing in imperviously sound tubes. One source of such gassing is the virtual leaking into the tube vacuum of "frozen" or stored hydrogen (and sometimes nitrogen) from certain vacuum envelope metals. Mechanisms that cause this gas storage are discussed, and experimental measurements of gas storage in certain body component parts are compared with the amounts of the same gases which were actually measured on tubes which failed because of delayed gassing. Other studies of a more qualitative nature include gases retained in carbon loaded porous ceramic rf mode absorbers, and the generation of gas at the surface of these and non-porous absorbers during tube operation. Studies have also been made of helium and argon diffusion and their possible storage in thin glass and ceramics in which very different mechanisms are involved.