Coincidence Doppler Broadening to Study the Chemical Environment at Positron Annihilation Sites

This paper introduces a Coincidence Doppler Broadening (CDB) analysis method, as presented during the Alfredo Dupasquier Summer School held in Brunate preceding the 2024 International Workshop on Positron Studies of Defects (PSD-24) in Como. CDB spectroscopy provides quantitative information on the chemical environment surrounding defects in various materials, including metal alloys, oxides, and polymers. Reference materials were analyzed to estimate the average chemical environment around defects, voids and porosities. The methodology is applied not only to homogeneous materials, such as metallic alloys, but also to investigate depth profiles in thin films of various materials. The statistical accuracy of element separation is also examined, along with the necessity to refine the method’s calibration through theoretical calculations and the integration of direct observation techniques.