PPPL-3553 is available in <a href="PPPL-3553.pdf">pdf</a> or 
<a href="PPPL-3553.ps">postscript</a> formats.

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<b>Effect of Boronization on Ohmic Plasmas in NSTX</b>
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<b>Authors:</b> C.H. Skinner, H. Kugel, R. Maingi, W.R. Wampler, W. Blanchard, M. Bell, R. Bell, B. LeBlanc, D.Gates, S. Kaye, P. LaMarche, J. Menard, D. Mueller, H.K. Na, N. Nishino, S. Paul, S. Sabbagh, V. Soukhanovskii
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<b>Original date of PPPL Report:</b> March 2001
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<p><B>Revised date of PPPL Report:</B> April 6, 2001</p>

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<b>Published in:</b> Nucl. Fusion <b>42</b> (March 2002) 329-332.</p>
 
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Boronization of the National Spherical Torus Experiment (NSTX) has enabled access to higher density, higher confinement plasmas. A glow discharge with 4 mTorr helium and 10% deuterated trimethyl boron deposited 1.7 g of boron on the plasma facing surfaces. Ion beam analysis of witness coupons showed a B+C areal density of 10<sup>18</sup> (B+C) cm<sup>-2</sup> corresponding to a film thickness of 100 nm. Subsequent ohmic discharges showed oxygen emission lines reduced by x15, carbon emission reduced by two and copper reduced to undetectable levels. After boronization, the plasma current flattop time increased by 70% enabling access to higher density, higher confinement plasmas.






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