Proton scattering from tungsten fuzz

Tungsten fuzz is a nanostructure formed on tungsten surface under helium plasma impact. In this work, we investigate this structure using the scattering of keV-energy protons. Energy spectra of scattered protons have double-peak shape that corresponds to the scattering from fuzz and underlying pure tungsten. The energy losses of protons in fuzz are estimated as the difference between primary beam energy and the energy corresponding to the local minimum between two peaks. Computer simulations with SRIM code also demonstrate double-peak shape of energy spectra of protons scattered from fuzzy target. Fuzz and pure tungsten stopping powers for protons are compared and fuzz density relative to pure tungsten is estimated and discussed. Evolution of H+ energy spectra during fuzz irradiation by Ar+ beam is measured and discussed.