Answers are grounded in this paper and cite their sources.
Measurements on bombardment-enhanced thermionic emission from oxide cathodes show that (a) the effect is not related to normal fading and recovery of thermionic emission; (b) the emitted electrons have energies in the thermal range rather than in the secondary range. Calculations indicate that the electron bombardment releases more than enough internal secondaries to account for the effect as increased thermionic emission. A more comprehensive theory is needed for explaining why the observed effect is not even larger.
No takes yet. Share an insight, caveat, or question.
J. B. Johnson (1951) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: