Enhanced sensitivity beam emission spectroscopy system for nonlinear turbulence measurements. Gupta, D. K., Fonck, R. J., McKee, G. R., Schlossberg, D. J., & Shafer, M. W. Review of Scientific Instruments, 75(10):3493--3495, October, 2004. 00042
Enhanced sensitivity beam emission spectroscopy system for nonlinear turbulence measurements [link]Paper  doi  abstract   bibtex   
An upgraded beam emission spectroscopy (BES) system has been deployed to access low amplitude turbulence regions near internal transport barriers on the DIII-D tokamak. Sixteen high sensitivity channels are being installed. A significant increase in total signal to noise is achieved by: (1) Increased spatial volume sampling tailored to known turbulence characteristics; (2) An increased throughput spectrometer assembly to isolate the local beam fluorescence, coupled to new large area photoconductive photodiodes; (3) A new sharp edge interference filter designed to optimize detection of the beam emission plus a significant fraction of the thermal deuterium charge exchange. A new data acquisition system has been installed, providing an eight times increase in integration time or an increased sample rate. Preliminary results from the upgraded system show a signal enhancement of greater than an order of magnitude. A clear broadband density fluctuation signal is observed in H-mode discharges with the upgraded BES system, demonstrating the significant performance enhancement.
@article{gupta_enhanced_2004,
	title = {Enhanced sensitivity beam emission spectroscopy system for nonlinear turbulence measurements},
	volume = {75},
	issn = {0034-6748, 1089-7623},
	url = {http://scitation.aip.org/content/aip/journal/rsi/75/10/10.1063/1.1787951},
	doi = {10.1063/1.1787951},
	abstract = {An upgraded beam emission spectroscopy (BES) system has been deployed to access low amplitude turbulence regions near internal transport barriers on the DIII-D tokamak. Sixteen high sensitivity channels are being installed. A significant increase in total signal to noise is achieved by: (1) Increased spatial volume sampling tailored to known turbulence characteristics; (2) An increased throughput spectrometer assembly to isolate the local beam fluorescence, coupled to new large area photoconductive photodiodes; (3) A new sharp edge interference filter designed to optimize detection of the beam emission plus a significant fraction of the thermal deuterium charge exchange. A new data acquisition system has been installed, providing an eight times increase in integration time or an increased sample rate. Preliminary results from the upgraded system show a signal enhancement of greater than an order of magnitude. A clear broadband density fluctuation signal is observed in H-mode discharges with the upgraded BES system, demonstrating the significant performance enhancement.},
	number = {10},
	urldate = {2014-05-28TZ},
	journal = {Review of Scientific Instruments},
	author = {Gupta, Deepak K. and Fonck, Raymond J. and McKee, George R. and Schlossberg, David J. and Shafer, Morgan W.},
	month = oct,
	year = {2004},
	note = {00042},
	keywords = {EMISSION SPECTROSCOPY, Internal transport barrier, Nonlinear dynamics, Nonlinear spatial filters, Turbulent flows},
	pages = {3493--3495}
}
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