Secondary Emission from Nickel by Impact of Metastable Atoms and Positive Ions of Helium

Abstract

Experiments on the secondary electron emission from Ni electrodes due to bombardment by positive ions and metastable atoms in a helium discharge under conditions similar to those obtaining in a glow discharge are reported. The method of measurement is similar to that of Uyterhoeven and ${\mathrm{Harrington}.\mathrm{}}^1$ The proportion of the measured current at the cathode which is carried by electrons is found to be 15 to 50 percent depending on experimental conditions. Similarly the number of electrons per slow positive ion is found to range between about 8 and 20 percent. The secondary electrons originate at the surface of the collector with about 15 volts maximum initial energy.