Note: A simple charge neutralization method for measuring the secondary electron yield of insulators

We report on a simple and effective charge neutralization method for measuring the total electron-induced secondary electron yield of insulators in a measurement system with a single pulsed electron gun. In this method, the secondary electron collector is negatively biased with respect to the sample to force some emitted secondary electrons to return to the sample surface and therefore to neutralize positive charges accumulated in the sample during the previous measurement. The adequate negative bias is determined and the equilibrium state of negative charging is discussed. The efficacy of the method is demonstrated by the measured electron yields in the cases with and without charge neutralization and by comparison with existing electron yield data of polyimide.