Method of Measuring the Normal Velocity Distribution of Secondary Electrons at Low Primary Bombarding Energies

Experimental apparatus designed to measure the secondary electron emission from solids at low primary electron energies is described. The design permits the determination of the normal velocity distribution of secondary electrons off insulating targets. Some of the usual difficulties associated with measurements of this kind are avoided through the use of an orthicon-type deflection system to separate primary and secondary beams. Measurements of the secondary emitting properties of molybdenum, some of which are performed under pulse conditions appropriate for insulating targets, are described and serve to demonstrate the performance of the apparatus.