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

The density and size of neon bubbles have been studied for the fluences of 6.2×{}10¹⁹ to 9.4×{}10²¹ 60-keV (²²{Ne}⁺$ ions)/${m}²$ in the bcc metals Mo and Ta and in the amorphous ${Ta}₂O₅ by means of the Doppler-shift attenuation method through the reaction ²²0ex0ex(p,{γ}) ²³Na. The concentration dependence of the bubble size was determined. Atomic Ne densities within the bubbles derived from the bubble sizes indicate overpressurized Ne bubbles in Mo and Ta in contrast to thermal equilibrium bubbles in Ta₂{O}₅$.