The experimental results on ion-induced hillocks on mica were analyzed in the range of 0.025 < E < 35 MeV/nucleon. The thermal spike was characterized quantitatively by the parameters derived in our previous track studies. The hillock height h varies linearly with the spike energy ε = gSe + βSn with a threshold εth = 3.8 keV/nm, where Se and Sn are the electronic and nuclear stopping powers and g is the efficiency. A calculation by the SRIM code provides β = 0.9 and 0.33 for Cn and Cun, Gen ions, respectively. From the slope of the h-ε line we obtained v/D = 0.36 nm-1, where v is the velocity of emergence of the hillocks and D is the thermal diffusivity. Our estimate is D < 0.057 cm2/s in the spike, which is much lower than the value, obtained by the free electron approximation. The results confirm on an absolute scale that only about 17/40% of Se is transferred into thermal energy at high/low E values and the equilibrium melting point is a good parameter in the conditions of a spike.
|Number of pages||5|
|Journal||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|Publication status||Published - May 1 2002|
- Ion irradiation
- Thermal spike
ASJC Scopus subject areas
- Nuclear and High Energy Physics