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Title: A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts

Abstract

A high-speed, non-invasive velocity diagnostic has been developed for measuring plasma rotation. The Doppler shift is determined by employing two detectors that view line emission from the identical volume of plasma. Each detector views through an interference filter having a passband that varies linearly with wavelength. One detector views the plasma through a filter whose passband has a negative slope and the second detector views through one with a positive slope. Because each channel views the same volume of plasma, the ratio of the amplitudes is not sensitive to variations in plasma emission. With suitable knowledge of the filter characteristics and the relative gain, the Doppler shift is readily obtained in real time from the ratio of two channels without needing a low throughput spectrometer. The systematic errors--arising from temperature drifts, stability, and frequency response of the detectors and amplifiers, interference filter linearity, and ability to thoroughly homogenize the light from the fiber bundle--can be characterized well enough to obtain velocity data with + or - 1 km/sec with a time resolution of 0.3 msec.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab., Princeton, NJ (US)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
828607
Report Number(s):
PPPL-3994
TRN: US0404038
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 9 Aug 2004
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLIFIERS; AMPLITUDES; FIBERS; PLASMA; ROTATION; STABILITY; TIME RESOLUTION; VELOCITY; DIAGNOSTICS; DOPPLER EFFECT

Citation Formats

Paul, S F, Cates, C, Mauel, M, Maurer, D, Navratil, G, and Shilov, M. A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts. United States: N. p., 2004. Web. doi:10.2172/828607.
Paul, S F, Cates, C, Mauel, M, Maurer, D, Navratil, G, & Shilov, M. A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts. United States. https://doi.org/10.2172/828607
Paul, S F, Cates, C, Mauel, M, Maurer, D, Navratil, G, and Shilov, M. Mon . "A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts". United States. https://doi.org/10.2172/828607. https://www.osti.gov/servlets/purl/828607.
@article{osti_828607,
title = {A High-Speed Optical Diagnostic that uses Interference Filters to Measure Doppler Shifts},
author = {Paul, S F and Cates, C and Mauel, M and Maurer, D and Navratil, G and Shilov, M},
abstractNote = {A high-speed, non-invasive velocity diagnostic has been developed for measuring plasma rotation. The Doppler shift is determined by employing two detectors that view line emission from the identical volume of plasma. Each detector views through an interference filter having a passband that varies linearly with wavelength. One detector views the plasma through a filter whose passband has a negative slope and the second detector views through one with a positive slope. Because each channel views the same volume of plasma, the ratio of the amplitudes is not sensitive to variations in plasma emission. With suitable knowledge of the filter characteristics and the relative gain, the Doppler shift is readily obtained in real time from the ratio of two channels without needing a low throughput spectrometer. The systematic errors--arising from temperature drifts, stability, and frequency response of the detectors and amplifiers, interference filter linearity, and ability to thoroughly homogenize the light from the fiber bundle--can be characterized well enough to obtain velocity data with + or - 1 km/sec with a time resolution of 0.3 msec.},
doi = {10.2172/828607},
url = {https://www.osti.gov/biblio/828607}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2004},
month = {8}
}