Low-noise, high-speed detector development for optical turbulence fluctuation measurements for NSTX
A new beam emission spectroscopy (BES) diagnostic is under development. Photon-noise limited measurements of neutral beam emissions are achieved using photoconductive photodiodes with a novel frequency-compensated broadband preamplifier. The new BES system includes a next-generation preamplifier and upgraded optical coupling system. Notable features of the design are surface-mount components, minimized stray capacitance, a wide angular acceptance photodiode, a differential output line driver, reduced input capacitance, doubling of the frequency range, net reduced electronic noise, and elimination of the need for a cryogenic cooling system. The irreducible photon noise dominates the noise up to 800 kHz for a typical input power of 60 nW. This new assembly is being integrated into an upgraded multichannel optical detector assembly for a new BES system on the NSTX experiment. © 2010 American Institute of Physics.
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Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Related Subject Headings
- Applied Physics
- 51 Physical sciences
- 40 Engineering
- 34 Chemical sciences
- 09 Engineering
- 03 Chemical Sciences
- 02 Physical Sciences