On opportunity of droplet sputtering of heavy metals by heavy ions of low and intermediate energies

Abstract

A droplet sputtering of heavy metals by heavy ions in energy range of elastic loss domination is theoretically investigated. It is shown that the droplet sputtering is possible at ion energies  both below and above the maximum permissible energy of nonlocal thermoelastic peak (NTP_<) formation ‑ a singly connected overheated region approximated by spherical segment. At E < E_NTP melt emission from subsurface NTP_< is possible in the range of ion energies E₁< E <E₂, and quantity E₁ and E₂ depend on sort of bombarding ions and structure of target material. At  >  the droplet sputtering provides nonlocal thermoelastic peak (NTP_>), forming from subsurface subcascade and/or on cross of several subsurface subcascades. Localization, size and energy content NTP_>, being random quantities, were determined by modeling with program package SRIM2008. Parameters and probability of NTP_> forming, providing the droplet sputtering and cratering are determinated at ion energies E = 200 keV in cases of combinations “ion Au⁺ in Au” and “ion U⁺ in U”. Estimates of sputtering yields of droplet sputtering are determinated in the viewed cases.