Farida Selim¹, Sahil Agarwal¹, Aaron Kohnert², Jacob Cooper³, Nan Li², Yongqiang Wang², Djamel Kaoumi³, Danny Edwards⁴, Laurent Capolungo⁴, Peter Hosmann⁵, Blas Uberuaga²; ¹Bowling Green State University, ²Los Alamos National Laboratory, ³North Carolina State University, ⁴Pacific Northwest National Laboratory, ⁵ University of Califorina, Berkeley

Positron annihilation spectroscopy (PAS) is as a powerful tool for measuring atomic scale defects as well as characterizing them and distinguishing between isolated vacancies, dislocations and vacancy clusters. In this study we combine high resolution transmission electron microscopy (HRTEM) and PAS to study defect production and evolution in ion irradiated Fe and Fe alloys. Both Positron annihilation lifetime spectroscopy (PALS) and Doppler broadening spectroscopy (DBS) of annihilation radiation were carried out to provide qualitative and quantitative information about the size and density of vacancies and clusters, while TEM measurements provided information about larger clusters and voids,The measurements reveal how the original point defects and dislocations in Fe films evolve with irradiation and the impact of alloying on their evolution or annihilation. We further calculate the density of each defect type and monitor both the change of defect structure and their electronic structure with irradiation dose and alloying.