PPPL-5042


<p><b>In-situ Measurement of Low-Z Material Coating Thickness on High Z Substrate for Tokamaks</b></p>
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<b>Authors:</b><span class="author"> D. Mueller, A.L. Roquemore, M. Jaworski, C.H. Skinner, J. Miller, A. Creely, P.
Raman, and D. Ruzic </span></p>
<p><b>Abstract:</b> Rutherford backscattering (RBS) of energetic particles can be used to determine the thickness of a coating of a low-Z material<br />
  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<sup>2</sup> 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.<br>
    
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  <b> Presented at:</b> the 20th Topical Conference on High-Temperature Plasma Diagnostics (HTPD 2014), Atlanta, Georgia, June 1-5, 2014 <br />
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  <b>Submitted to: </b>Review of Scientific Instruments<br>
  
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  <a href="PPPL-5042.pdf"><b>Download PPPL-5042</b></a> (pdf   2.81MB; 3pp)
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