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Title: Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade

Abstract

Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements.

Authors:
; ; ; ; ; ; ; ;  [1];  [2]
  1. Association Euratom - Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark)
  2. DTU Elektro, Technical University of Denmark, DK-2800 Lyngby (Denmark)
Publication Date:
OSTI Identifier:
22063772
Resource Type:
Journal Article
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 83; Journal Issue: 1; Other Information: (c) 2012 EURATOM; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6748
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ASDEX TOKAMAK; CYCLOTRON RADIATION; DESIGN; ELECTRIC POTENTIAL; ELECTROMAGNETIC FILTERS; ELECTRON EMISSION; EV RANGE; GHZ RANGE; IONS; MICROWAVE AMPLIFIERS; MICROWAVE RADIATION; PERFORMANCE; PLASMA; POWER DENSITY; SIGNALS; SPECTRAL RESPONSE; STRAY RADIATION; THOMSON SCATTERING; TRANSMISSION

Citation Formats

Furtula, V, Salewski, M, Leipold, F, Michelsen, P K, Korsholm, S B, Meo, F, Moseev, D, Nielsen, S K, Stejner, M, and Johansen, T. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade. United States: N. p., 2012. Web. doi:10.1063/1.3675886.
Furtula, V, Salewski, M, Leipold, F, Michelsen, P K, Korsholm, S B, Meo, F, Moseev, D, Nielsen, S K, Stejner, M, & Johansen, T. Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade. United States. doi:10.1063/1.3675886.
Furtula, V, Salewski, M, Leipold, F, Michelsen, P K, Korsholm, S B, Meo, F, Moseev, D, Nielsen, S K, Stejner, M, and Johansen, T. Sun . "Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade". United States. doi:10.1063/1.3675886.
@article{osti_22063772,
title = {Design and performance of the collective Thomson scattering receiver at ASDEX Upgrade},
author = {Furtula, V and Salewski, M and Leipold, F and Michelsen, P K and Korsholm, S B and Meo, F and Moseev, D and Nielsen, S K and Stejner, M and Johansen, T},
abstractNote = {Here we present the design of the fast-ion collective Thomson scattering receiver for millimeter wave radiation installed at ASDEX Upgrade, a tokamak for fusion plasma experiments. The receiver can detect spectral power densities of a few eV against the electron cyclotron emission background on the order of 100 eV under presence of gyrotron stray radiation that is several orders of magnitude stronger than the signal to be detected. The receiver down converts the frequencies of scattered radiation (100-110 GHz) to intermediate frequencies (IF) (4.5-14.5 GHz) by heterodyning. The IF signal is divided into 50 IF channels tightly spaced in frequency space. The channels are terminated by square-law detector diodes that convert the signal power into DC voltages. We present measurements of the transmission characteristics and performance of the main receiver components operating at mm-wave frequencies (notch, bandpass, and lowpass filters, a voltage-controlled variable attenuator, and an isolator), the down-converter unit, and the IF components (amplifiers, bandpass filters, and detector diodes). Furthermore, we determine the performance of the receiver as a unit through spectral response measurements and find reasonable agreement with the expectation based on the individual component measurements.},
doi = {10.1063/1.3675886},
journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 1,
volume = 83,
place = {United States},
year = {2012},
month = {1}
}