Secondary Emission by Positive Ion Bombardment

The investigation was undertaken primarily to determine the ratio of the secondary electron current to the primary ion current, $\frac{i_s}{i_p}$, for mercury ions bombarding a mercury target. The beam constituted a source of continually renewed surface of the target material. By varying the electron accelerating potential in the ion source, the proportions of the various types of ions present in the beam were altered. Thus the influence of mercury ions having different charges upon the secondary electron yield was determined. Some work was also done with cadmium ions bombarding a cadmium target.