Positron Lifetime Study Of Proton-Irradiated Molybdenum

Polycrystalline Mo samples of 99.93% purity were irradiated at room temperature with 3.2 MeV protons. The radiation damage and lattice defect annealing were studied by positron lifetime spectroscopy in the temperature range from 293 to 1138 K. It was found that microvoids containing 2 to 3 vancancies were formed after the irradiation and the number of microvoids increased with increasing dose. The void growth and the influence of hydrogen atoms on the void growth after successively higher temperature annealing were clearly detected through the changes in positron lifetime parameters and are discussed in detail.