Energy and temperature dependences of ion-induced electron emission from polycrystalline graphite

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2011-05, Vol.269 (9), p.995-998
• Main Authors: Avilkina, V.S., Andrianova, N.N., Borisov, A.M., Mashkova, E.S., Parilis, E.S.
• Format: Article
• Language: English
• Subjects: Electron emission; Energy (nuclear); Energy use; Graphite; High-fluence ion irradiation; Ion-induced electron emission; Radiation damage; Radiation damage in carbon-based materials; Steady state; Temperature dependence; Thresholds
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2010.12.030

The dependences of the yield γ of ion-induced kinetic electron emission from polycrystalline graphite on ion energy E were measured under high-fluence Ar + and N 2 + ion irradiation in energy range 6–30 keV from room temperature to 400 °C. It has been observed that the step-like pattern of temperature dependence γ( T) at the dynamic radiation damage annealing temperature T a is gradually transformed with decreasing ion energy until γ virtually ceases to depend on temperature. The experimentally obtained energy dependence of the ratio γ( T > T a)/ γ( T < T a) has been analyzed using the theory of ion-induced kinetic electron emission. Some threshold values of the level of radiation damage ν d measured in dpa under steady state of high-fluence Ar + and N 2 + irradiation have been found. When ν becomes less than a threshold value ν d, the graphite lattice is virtually not disordered. It has been found that ν d for Ar + ions is greater than ν d for N 2 + ions.