Electron Emission from Thoriated Tungsten

Constants of the electron emission from a monatomic layer of thorium on tungsten at temperatures from 1000^∘{} to 2000^∘{}K.---The electron emission for a monatomic layer of thorium on tungsten is best represented for zero field strength by the relation I=3T²ε^-30,500/T, where I is expressed in amps/cm². The emission was measured for different states of activation of the filament. If we let θ be the fraction of surface covered with thorium, then for θ<0.95 (approximately) logA_θ varies linearly with b_θ where the emission for the given surface is represented by I=A_θT²ε^-b_θT. It is also pointed out that the emission for a monatomic film of thorium on tungsten is greater than that observed for metallic thorium.