TITLE

The NSTX fast-ion D-alpha diagnostic

AUTHOR(S)
Podestà, M.; Heidbrink, W. W.; Bell, R. E.; Feder, R.
PUB. DATE
October 2008
SOURCE
Review of Scientific Instruments;Oct2008, Vol. 79 Issue 10, p10E521
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A new diagnostic, aimed at energy-resolved measurements of the spatial and temporal dynamics of fast ions in NSTX plasmas, is described. It is based on active charge-exchange recombination spectroscopy. The fast-ion signal is inferred from light emitted in the wavelength range of the Dα line by fast ions recombining with an injected neutral beam. Two complementary systems are operational. The first system, based on a spectrometer coupled to a charge coupled device detector, has 16 channels with space, time, and energy resolution of 5 cm, 10 ms, and 10 keV, respectively. The second system monitors the energy-integrated fast-ion signal on time scales of ∼20 μs at three different radii. Signals are measured by a multianode photomultiplier tube. For both systems, each channel includes two paired views, intercepting and missing the neutral beam for a direct subtraction of the background signal not associated with fast ions. Examples of signals from the 2008 NSTX run are presented.
ACCESSION #
35150227

 

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