Helium plasma irradiation on single crystal tungsten and undersized atom doped tungsten alloys

Helium plasma irradiation leads to the formation of nanostructures on the surface when certain conditions are satisfied. The surface morphology changes due to helium plasma irradiation were investigated on single crystal tungsten samples with different crystal orientations. Differences in surface morphology changes were observed in (100) and (110) single crystal tungsten samples when the helium fluence was less than 10(25) m(-2). However, the differences disappeared as growth proceeded. Tungsten alloys were prepared in order to investigate the influence of the additional undersized atomic species on nanostructure growth. The influence of the doping of undersized atoms, i.e. 2 at% Fe doped and 2 at% Cr doped atoms, is presented.