Multiply charged ion-induced secondary electron emission from metals relevant for laser ion source beam diagnostics

The number of secondary electrons, γ, emitted when multiply charged ions impact on metallic probe surface was measured to make the quantitative ion diagnostics based on this process more precise. The electron yield γ(q,E i ) was measured for Ta q+ and Xe q+ ions (q=6–41) in the region of ion kinetic energy per atomic mass up to E i /A∼34 keV / amu . For highly charged Xe q+ ions (q>16), a minimum of the electron yield, γ MIN , was observed in its dependence on E i . With increasing q, the γ MIN shifts to higher energies. The comparison of available data for N q+ , Ne q+ , Ar q+ , Xe q+ , and Au q+ ions shows that one can create a similarity law describing the dependence of γ MIN for those elements in the E i /A representation. The value of γ/q evaluated from compiled data ranges from ≈0.3 to ≈3.5 in dependence on q and E i .