Initial results of tests of depth markers as a surface diagnostic for fusion devices
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Author(s)
Hartwig, Z. S.
Wright, G. M.
Kesler, Leigh Ann
Sorbom, Brandon Nils
Barnard, Harold Salvadore
Whyte, Dennis G
Date Issued
December 2016
Journal
Nuclear Materials and Energy
Publisher
Elsevier
Citation
Kesler, L.A., B.N. Sorbom, Z.S. Hartwig, H.S. Barnard, G.M. Wright, and D.G. Whyte. “Initial Results of Tests of Depth Markers as a Surface Diagnostic for Fusion Devices.” Nuclear Materials and Energy 12 (August 2017): 1277–1281. © 2016 Published by Elsevier Ltd.
Version
Final published version
Abstract
The Accelerator-Based In Situ Materials Surveillance (AIMS) diagnostic was developed to perform in situ ion beam analysis (IBA) on Alcator C-Mod in August 2012 to study divertor surfaces between shots. These results were limited to studying low-Z surface properties, because the Coulomb barrier precludes nuclear reactions between high-Z elements and the ∼1 MeV AIMS deuteron beam. In order to measure the high-Z erosion, a technique using deuteron-induced gamma emission and a low-Z depth marker is being developed. To determine the depth of the marker while eliminating some uncertainty due to beam and detector parameters, the energy dependence of the ratio of two gamma yields produced from the same depth marker will be used to determine the ion beam energy loss in the surface, and thus the thickness of the high-Z surface. This paper presents the results of initial trials of using an implanted depth marker layer with a deuteron beam and the method of ratios. First tests of a lithium depth marker proved unsuccessful due to the production of conflicting gamma peaks, among other issues. However, successful trials with a boron depth marker show that it is possible to measure the depth of the marker layer with the method of gamma yield ratios.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
Massachusetts Institute of Technology. Plasma Science and Fusion Center
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Creative Commons Attribution-NonCommercial-NoDerivs License
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DOI of Published Version
http://dx.doi.org/10.1016/J.NME.2016.11.013
