The solution proposed for solving the problem presented by the porous tungsten wall used in the ionization of cesium by contacts consists essentially of hampering the tungsten recrystallization mechanism by introducing a dispersed thoria phase and of developing nonmachined walls by incorporating a sublimable plastic paste which permits the calendering and stamping of thin sheets in the appropriate matrix. This process permitted the production of pieces of various shapes including flat wafers, or curvated pellets, flat or curvated strip with rectangular or rounded extremities. The porosity, which is determined by the proportion of the plastic paste, can vary between 25% and 40%. The pores, 1 to 3 microns in dimension, number 20 to 30 million by cm2. The results appear favorable concerning the neutral rate, the permeability and the ageing effects.
Metallurgy of thoriated tungsten powder and realisation of ionisers
Metallurgie von thoriertem Wolframpulver und Aufbau von Ionenquellen
Titel franzoesisch
Acta Electronica ; 17 , 4 ; 415-420
1974
, 9 Quellen
Article (Journal)
French
CAESIUM , IONENQUELLE , WOLFRAM , THORIUM , METALLURGIE