Density and size of neon bubbles in molybdenum, tantalum, and tantalum oxide

Abstract

The density and size of neon bubbles have been studied for the fluences of 6.2\ifmmode\times\else\texttimes\fi{}${10}^{19}$ to 9.4\ifmmode\times\else\texttimes\fi{}${10}^{21}$ 60-keV ${(}^{22}$${\mathrm{Ne}}^{+}$ ions)/${\mathrm{m}}^{2}$ in the bcc metals Mo and Ta and in the amorphous ${\mathrm{Ta}}_{2}$${\mathrm{O}}_{5}$ by means of the Doppler-shift attenuation method through the reaction $^{22}\phantom{\rule{0ex}{0ex}}(\mathit{p}$,\ensuremath{\gamma}) ${\mathrm{}}^{23}$Na. The concentration dependence of the bubble size was determined. Atomic Ne densities within the bubbles derived from the bubble sizes indicate overpressurized Ne bubbles in Mo and Ta in contrast to thermal equilibrium bubbles in ${\mathrm{Ta}}_{2}$${\mathrm{O}}_{5}$.