Schematic of dust detector (not to scale) showing interlocking combs of traces. Dust impinging on the traces causes a short circuit and a voltage signal is generated across the resistor.
Dust detector before installation in NSTX.
Poloidal cross section of NSTX vessel with close up of dust detector.
Schematic of differential detection electronics. See text for explanation of components.
Signal generated by laboratory dust source incident on detector as recorded by the NSTX data acquisition system.
Response of 50.8 mm detector to carbon dust in vacuum, using a 50 V bias, differential counting electronics, and mesh cover. The line is a linear fit to the data
(a) Dust signal; there is a total of 64 counts from dust. (b) The simultaneous null signal from the covered detector.
(a) Time history of channel 1 (open detector) and channel 2 (covered detector) signals vs shot number over July and August 2009. The points where the Li aerosol was operated are distinguished in the legend. Note the two-order-of-magnitude increase in signal with the operation of the Bay C Li aerosol.
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