First Real-Time Detection of Surface Dust in a Tokamak
Authors: C. Skinner, B Rais, A.L. Roquemore, H.W. Kugel, R. Marsala, T. Provost
Abstract:
The first real-time detection of surface dust inside a tokamak was made using an electrostatic dust detector. A fine grid of interlocking circuit traces was installed in the NSTX vessel and biased to 50 v. Impinging dust particles created a temporary short circuit and the resulting current pulse was recorded by counting electronics. The techniques used to increase the detector sensitivity by a factor of x10,000 to match NSTX dust levels while suppressing electrical pickup are presented. The results were validated by comparison to lab measurements, by the null signal from a covered detector that was only sensitive to pickup, and by the dramatic increase in signal when Li particles were introduced for wall conditioning purposes.
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Submitted to: Review of Scientific Instruments (May 2010)
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Download PPPL-4517 (pdf 191 KB 5 pp)
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