Using depth markers and ion beam analysis to decipher divertor erosion

Leigh Ann Kesler


Tuesday, October 31, 2017



PSFC Student Seminars

There are several challenges to adapting traditional IBA to be useful in tokamak studies, which this research is addressing in two ways. One is by adapting the techniques to more accurately study bulk properties. The other is finding ways to do this analysis in situ. The Accelerator-based In situ Materials Surveillance (AIMS) diagnostic was developed as an in situ IBA diagnostic to monitor erosion, film deposition, and tritium fuel retention in magnetic fusion devices. AIMS was used at the end of the FY2012 Alcator C-Mod campaign to successfully demonstrate the viability of using in situ IBA to measure low-Z erosion in a tokamak using nuclear reaction analysis (NRA) [1]. The next step, explored in this talk, will be to study the erosion of the bulk high-Z components of the divertor, such as tungsten and molybdenum. In order to look at the high-Z elements that are out-of-range for direct, nuclear reactions, a method using implanted depth markers is being utilized. This talk will explore the theory behind depth markers, the challenges associated with implanting layers with an ion beam, and intricacies of analyzing this data.