Absolute wavelength calibration of a Doppler spectrometer with a custom Fabry-Perot optical system
| Autor: | M. Baltzer, T. Nishizawa, Mark Nornberg, Darren Craig, D.J. Den Hartog |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Physics Observational error Spectrometer business.industry Holography 01 natural sciences Flow measurement 010305 fluids & plasmas law.invention symbols.namesake Optics law 0103 physical sciences symbols Calibration Plasma diagnostics business Instrumentation Doppler effect Fabry–Pérot interferometer |
| Zdroj: | The Review of scientific instruments. 87(11) |
| ISSN: | 1089-7623 |
| Popis: | An Ion Doppler Spectrometer (IDS) is used for fast measurements of C VI line emission (343.4 nm) in the Madison Symmetric Torus. Absolutely calibrated flow measurements are difficult because the IDS records data within 0.25 nm of the line. Commercial calibration lamps do not produce lines in this narrow range. A light source using an ultraviolet LED and etalon was designed to provide a fiducial marker 0.08 nm wide. The light is coupled into the IDS at f/4, and a holographic diffuser increases homogeneity of the final image. Random and systematic errors in data analysis were assessed. The calibration is accurate to 0.003 nm, allowing for flow measurements accurate to 3 km/s. This calibration is superior to the previous method which used a time-averaged measurement along a chord believed to have zero net Doppler shift. |
| Databáze: | OpenAIRE |
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