Prof. Mike Short & Mr. Cody Denett, MIT, USA

Real-time property monitoring during ion beam irradiation using transient grating spectroscopy (Denett)
When Jul 20, 2018
from 09:30 AM to 10:30 AM
Where LR8
Contact Name
Contact Phone 01865-283446
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Abstract: Currently, there exist few methods for characterizing irradiated material performance in situ, during exposure. Techniques such as in situ TEM or in situ Raman spectroscopy can provide local structural information during irradiation, but no current methods are able to continuously monitor bulk thermal and mechanical properties. The ability to observe changes in these properties in real time would allow for high-resolution mapping of dose-property relationships at a fidelity not previously possible. In addition, such a tool could be used for detecting emergent irradiation-induced microstructural evolution such as the transition from incubation to steady-state void swelling. Transient grating spectroscopy (TGS) is a non-contact, non-destructive methodology suited for this purpose. By optically inducing and monitoring monochromatic surface acoustic waves (SAWs), the thermal diffusivity and elastic properties of materials may be determined. A time-resolved implementation of this technique has been developed with sufficient sensitivity to continuously monitor microstructural evolution during irradiation. An in situ TGS beamline experiment for concurrent ion beam irradiation and property monitoring is currently in use on a 6 MV tandem accelerator at Sandia National Laboratories (Albuquerque, NM, USA). Using high-energy heavy ions (30-35 MeV), radiation damage effects on the thermomechanical properties of pure metals including Cu, W, Ni, and Fe are being studied with a dose resolution on the order of 0.05 dpa/measurement for elastic properties (up to 100 dpa at peak). These methods will not only allow for dose-property relationships to be studied in much greater detail than previously possible but also provide rapid, engineering-relevant data capable of speeding the innovation cycle in nuclear material development.