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Title: 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.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. PPPL
  2. 2University of Illinois, Champaign, IL, USA
Publication Date:
OSTI Identifier:
1172634
Report Number(s):
PPPL-5042
Journal ID: ISSN 0034--6748
DOE Contract Number:
DE-AC02-09CH11466
Resource Type:
Conference
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.
Publisher:
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
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY