Ponentes
Descripción
The development of fusion energy systems requires advanced diagnostic techniques capable of characterizing radiation-induced defects in structural and functional materials with high sensitivity. Positron annihilation lifetime spectroscopy (PALS) is one of the most powerful methods for investigating vacancy-type defects, vacancy clusters, free-volume nanostructures, and irradiation-induced damage at the atomic scale. However, the temporal resolution of conventional PALS instruments is typically limited to several hundred picoseconds, restricting the separation of closely spaced lifetime components associated with complex defect populations. We propose a novel Radio-Frequency Timer-Based Positron Annihilation Lifetime Spectroscopy (RF-PALS) instrument for advanced materials characterization. The concept builds upon a recently demonstrated radio-frequency timing technique that converts temporal information into spatial coordinates and has achieved better than 10 ps timing resolution in single-electron and single-photon measurements. Based on this approach, RF-PALS is expected to provide a lifetime resolution of approximately 10–30 ps, representing more than an order-of-magnitude improvement compared with conventional PALS systems. The enhanced temporal resolution will improve the sensitivity of positron lifetime measurements to vacancy defects, defect clusters, dislocation-related trapping sites, and nanoscale free-volume distributions generated by neutron irradiation. Such capability is expected to provide new opportunities for studying defect formation, migration, clustering, and recovery processes in fusion-relevant materials under extreme irradiation conditions.