High-performance double-filter soft x-ray diagnostic for measurement of electron temperature structure and dynamics

Journal Article · Mon Oct 15 00:00:00 EDT 2012 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4740274· OSTI ID:22093909

McGarry, M. B.; Den Hartog, D. J.; Goetz, J. A.; Thomas, M. A.; Reyfman, M.; Kumar, S. T. A. ^[1]; Franz, P. ^[2]

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1. Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
2. Consorzio RFX, Associazione Euratom-ENEA per la Fusione, Padova (Italy)

A new soft x-ray (SXR) T{sub e} and tomography diagnostic has been developed for MST that can be used for simultaneous SXR spectrum measurement, tomographically reconstructed emissivity, and reconstructed and line-of-sight electron temperature. The diagnostic utilizes high-performance differential transimpedance amplifiers (gain 10{sup 5}-10{sup 9}) to provide fast time response (up to 125 kHz), allowing for the study of plasma structure dynamics. SXR double-foil T{sub e} measurements are consistent with Thomson scattering. SXR brightness through a variety of filter thicknesses has been combined with charge exchange recombination spectroscopy (CHERS) impurity density measurements to determine the plasma energy spectrum. Magnetic pickup from the fluctuating magnetic fields in the plasma (B(tilde sign){approx}20 gauss at 10-20 kHz) has been dramatically reduced by improving the detector and housing design, so that nanoampere diode currents are now measured without interference from the substantial fluctuating magnetic field incident on the plasma facing surface of the probe.

• OSTI ID: 22093909
• Journal Information: Review of Scientific Instruments, Vol. 83, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BRIGHTNESS
CHARGE EXCHANGE
ELECTRON TEMPERATURE
EMISSIVITY
ENERGY SPECTRA
FLUCTUATIONS
FOILS
INERTIAL CONFINEMENT
INTERFERENCE
ION TEMPERATURE
MAGNETIC FIELDS
PLASMA DIAGNOSTICS
PLASMA IMPURITIES
SOFT X RADIATION
SPECTROSCOPY
THOMSON SCATTERING
TOMOGRAPHY
X-RAY SOURCES