Performance and life tests of various types of impregnated cathodes

Abstract The studies reported here involve a number of investigation methods suitable for characterizing and comparing the performances of B, S, M and mixed matrix cathodes (MM). Long term zero field saturation current, work function and evaporation rates of these cathodes have been measured for different temperatures. The exhaust of barium and calcium has been determined with the electron microprobe on fractures of B and S cathodes at different life time. X-ray patterns have shown for B and S cathodes the increase of stable Ba and Ca compounds with W and Al, and for M cathodes the presence of define phases such as W 2 Os. Current decay for S-type cathodes has been plotted after life time at different temperatures. A correlation has been found with the electron microprobe results and with the long term evaporation rates.