2005 Volume 46 Issue 3 Pages 565-567
Surface modification and internal damage of tungsten irradiated with 8 keV Helium (He) ions at 1273 K was observed by the complementary use of a scanning electron microscope (SEM), an atomic force microscope (AFM), and a transmission electron microscope (TEM). It was found that an irradiated surface was roughened by the formation of dense large bulges of 100–200 nm and small ones of a few nm in size. It was also observed that fine He bubbles ranging from a few to 100 nm were formed in the subsurface layer. These results indicate that roughening of a He+ ion irradiated surface at a high temperature results from the formation of bubbles just beneath the surface. Their thermal migration and coalescence under irradiation play an important role in the formation of various sized bubbles.
