In Situ Sample Thickness Monitoring in Simultaneous Irradiation-Corrosion Experiments

Irradiation-corrosion experiments have recently become a popular approach to studying the simultaneous effects of both extremes on materials. Each individual experiment requires extensive preparation and yields one sample exposed to one set of conditions (temperature, damage rate, etc.) that can then be analyzed ex situ. In this talk, we will discuss the potential for the in situ monitoring of long-term (hours to tens of hours) irradiation-corrosion experiments with ion beam analysis techniques, such as particle-induced x-ray emission spectroscopy (PIXE) and Rutherford backscatter spectroscopy (RBS). Both can be used to provide information about changes in the average sample thickness while under irradiation, which is tied to corrosion kinetics. We will lay out different options for the interpretation of PIXE data based on signal from the sample alone or a mixture of sample and corrosive medium signals. The different approaches allow the use of these techniques for different combinations of samples and corrosive media, such as water, heavy liquid metals, or molten salts. As an example, we will show recent experimental data for pure Fe under proton-irradiation simultaneously corroded by lead-bismuth eutectic (LBE), a Gen-IV nuclear reactor coolant. The Fe-LBE system provides the unique opportunity to compare the accuracy of the two data interpretation options for PIXE with each other as well as with RBS, all of which provide in situ insight into Fe corrosion under irradiation not attainable from ex situ observations.