Helium retention, bubble superlattice formation and surface blistering in helium-irradiated tungsten

The microstructural evolution and helium retention in polycrystalline tungsten (W) implanted with 100 keV helium ions at different temperatures to a wide range of different fluences were studied. Rutherford backscattering spectrometry (RBS) shows that helium atoms were well retained in tungsten, and no loss of helium occurred before surface blistering/flaking occurred. Within certain windows of fluence and temperature, ordered bubble...