Secondary Electron Emission from a Hot Nickel Target Due to Bombardment by Hydrogen Ions

Abstract

A hot nickel target was bombarded by hydrogen molecular ions to determine the number of secondary electrons emitted per positive ion at various voltages. The method used was that of Oliphant. The ions were drawn from a discharge, collimated by a narrow canal, bent by an electric field and allowed to impinge on the hot target. The latter was surrounded by a platinized bulb which served as a collector for the electrons. After the target had been kept hot for six weeks, values consistent among themselves could be obtained. The number of electrons elicited from the target per positive ion varied from 0.046 at 303 electron volts to 0.223 at 1539 electron volts ion energy. The number of reflected positive ions is a measurable fraction of the total positive ion beam.