SEDL / STP / STP300-EB / STP41242S

Mass Spectrometric Studies of Power Klystron Exhaust Processing

Noble, Lowell
Eitel-McCulloueh, Inc., San Bruno, Calif.

Waits, Robert K.
Eitel-McCulloueh, Inc., San Bruno, Calif.

Pages: 7    Published: Jan 1961

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Abstract

The partial pressures of the residual gases present during vacuum processing and operation of power klystrons were measured using a bakeable Diatron-20 mass analyzer tube. The gases present during bakeout at 500 C were, in decreasing abundance, hydrogen, water, carbon monoxide, carbon dioxide, and methane. Carbon dioxide, methane, and carbon monoxide predominated during the conversion of both oxide and nickel-matrix cathodes. Carbon monoxide was evolved when the tube body was bombarded by the electron beam. After seal-off, the residual gas pressure in the klystron was about 5 x 10^-7 Torr, consisting of carbon monoxide, methane, and hydrogen. One hundred hours of operation reduced the pressure to 4 x 10^-9 Torr. The remaining gases were carbon monoxide and hydrogen.