In-situ Measurement of Low-Z Material Coating Thickness on High Z Substrate for Tokamaks
Rutherford backscattering (RBS) of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 hours of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm^2 thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.
- Publication Date:
- OSTI Identifier:
- Report Number(s):
Journal ID: ISSN 0034--6748
- DOE Contract Number:
- Resource Type:
- Resource Relation:
- Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 11; Conference: 20th Topical Conference on High-Temperature Plasma Diagnostics (HTPD 2014), Atlanta, Georgia, June 1-5, 2014; Related Information: Proceedings of the 20th Topical Conference on High-Temperature Plasma Diagnostics, Atlanta, Georgia, June, 2014.
- Review of Scientific Instruments
- Research Org:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Sponsoring Org:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
- Country of Publication:
- United States
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
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