Quantitative analysis of rhenium in irradiated tungsten

Pure tungsten (W), irradiated to 3.5 dpa in a target of the Swiss neutron spallation source (SINQ), was characterized using high-sensitivity HPGe gamma ray spectroscopy identify present radionuclides. Synchrotron X-ray absorption used quantify amount Re produced W. An atomic concentration 0.61% W determined from height L3-edge edge jump. Analysis local structure extended fine (EXAFS) spectra indicates that rhenium (Re) system is mainly coordinated by atoms and partly void defects. First-principles density functional theory calculations confirm positive formation energy for double defect system, supporting conclusion cluster suppressed.