Calibration of phase contrast imaging on HL-2A Tokamak

Phase contrast imaging (PCI) has recently been developed on HL-2A tokamak. In this article we present the calibration of this diagnostic. This system is to diagnose chord integral density fluctuations by measuring the phase shift of a CO2 laser beam with a wavelength of 10.6 μm when the laser beam p...

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Bibliographic Details
Published inJournal of instrumentation Vol. 12; no. 10; p. C10005
Main Authors Yu, Y., Gong, S.B., Xu, M., Xiao, C.J., Jiang, W., Zhong, W.L., Shi, Z.B., Wang, H.J., Wu, Y.F., Yuan, B.D., Lan, T., Ye, M.Y., Duan, X.R.
Format Journal Article
LanguageEnglish
Published Bristol IOP Publishing 16.10.2017
Subjects
Calibration
Carbon dioxide
Carbon dioxide lasers
Diagnostic systems
Integrals
Laser beams
Lasers
Microscopes
Phase contrast
Plasma
Plasma density
Sound waves
Tokamak devices
Variations
Wavelengths
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Summary:Phase contrast imaging (PCI) has recently been developed on HL-2A tokamak. In this article we present the calibration of this diagnostic. This system is to diagnose chord integral density fluctuations by measuring the phase shift of a CO2 laser beam with a wavelength of 10.6 μm when the laser beam passes through plasma. Sound waves are used to calibrate PCI diagnostic. The signal series in different PCI channels show a pronounced modulation of incident laser beam by the sound wave. Frequency-wavenumber spectrum is achieved. Calibrations by sound waves with different frequencies exhibit a maximal wavenumber response of 12 cm−1. The conversion relationship between the chord integral plasma density fluctuation and the signal intensity is 2.3×1013 m−2/mV, indicating a high sensitivity.
ISSN:1748-0221
1748-0221
DOI:10.1088/1748-0221/12/10/C10005