Photoionization and breakdown

For some time it has been recognized that in the Townsend mechanism of breakdown, radiation is the only mechanism that appears to be fast enough to account for the speed of breakdown. Considerable attention has been directed to photoemission but this has been unable to account for observed phenomena. Recently data has been obtained which makes it possible to make quantitative determinations of photoionization. This paper describes calculations made using a digital computer to apply the available data on photoionization to the Townsend breakdown of gaps of the order of 1 cm at atmospheric pressure.