Formulae for low-energy secondary electron yield from different kinds of emitters as a function of measurable variables

Based on the characteristics of secondary electron emission and the relationships among parameters of secondary electron yield δ in the low-energy range of Ep0 ≦ Ep0m ≦ 800 eV (low-energy δ), the universal formula for low-energy δ as a function of Ep0, Ep0m and maximum δ(δm) was deduced, where Ep0 and Ep0m are the incident energies of primary electron and of δm, respectively. From the deduced universal formula and experimental low-energy δ from metals, semiconductors and insulators, special formula for low-energy δ from metals as a function of Ep0, Ep0m and δm and that for low-energy δ from semiconductors and insulators as a function of Ep0, Ep0m and δm were deduced, respectively. The results were analyzed, it can be concluded that the two deduced special formulae can be used to calculate low-energy δ from metals, semiconductors and insulators, respectively.