Positron lifetime study of molybdenum neutron-irradiated at various temperatures

Abstract Positron Lifetime measurements reveal that neutron irradiation at 350 and 400°C can produce sub-electron microscopic voids in Mo. The results show that the lifetime in voids reaches a saturation value with increasing void size to a dimension less than 20 A. It is suggested that the difference among known data for τ 2 ≲ 450 ps can be attributed to differences in the metal-void interface and gaseous conditions within the void.