Los Alamos National LaboratoryFUTURE: Fundamental Understanding of Transport Under Reactor Extremes
An Energy Frontier Research Center funded by the Department of Energy, Office of Basic Energy Sciences

Thrust 1: Point Defects

Develop an in situ positron annihilation spectroscopy system to characterize radiation-induced defect content during irradiation.

FUTURE is developing an in situ positron annihilation spectroscopy system that can characterize radiation-induced defect content during irradiation.

Context: During irradiation, energetic particles smashing into materials create a high concentration of non-equilibrium point defects, defects that wouldn't be there if there was no irradiation. These defects are all-important for driving the motion of atoms through the material, leading to changes in the chemical make-up and distribution of the material and the rates and mechanisms of corrosion. It is thus imperative to understand the nature of these defects.

Motivating Scientific Question: How do coupled extremes affect defect populations and kinetics?

Approach: FUTURE will use in situ transmission electron microscopy to look at materials as they are irradiated in the microscope. While this technique is blind to the very smallest defects, it can reveal the nature of larger defects -- dislocation loops and cavities -- that provide invaluable insight into how those smallest defects evolve. To address the smallest defects, FUTURE will pioneer the use of in situ positron annihilation spectroscopy to directly quantify the populations of point defects in the material as it is being irradiated, revealing the nature of those defects. This will not only provide unprecedented insight into what defects are produced during irradiation, but also serve as critical benchmark for the validation of computational models.

Thrust Lead: Farida Selim of Bowling Green State University.