Research Investigation of Cathode Emissive Materials

摘要

In a program of development of thorium impregnated tungsten matrix cathodes life studies have been extended to 6000 hours at 1 amp/cm at approximately 1550°CB, and 3500 hours at 2.4 amps/cm2 at approximately 1620oCB, both life figures subject to upward revision as tests continue.nAn experimental determination of preliminary character has been made of the surface density of thorium on tungsten corresponding to the emission maximum.nRelevant to studies concerning the possibility of desorption of thorium by electron bombardment, work is in progress regarding thermal deactivation (evaporation) rates as a function of temperature and coverage.nExperiments are described concerning "knife-edge" seal techniques for dry box closure of experimental tubes which must thereafter have extensive baking.