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SPECTROSCOPIC DIAGNOSTIC COMPLEX FOR STUDYING PULSED TOKAMAK PLASMA. Yu. Golubovskii, Yu. Ionikh, A. Mestchanov, V. Milenin, I. Porokhova, N. Timofeev Saint-Petersburg State University, Physical Faculty, Optics Department, Saint-Petersburg, Russia. 4 October 2005, Saint-Petersburg.
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SPECTROSCOPIC DIAGNOSTIC COMPLEX FOR STUDYING PULSED TOKAMAK PLASMA Yu. Golubovskii, Yu. Ionikh, A. Mestchanov, V. Milenin, I. Porokhova, N. Timofeev Saint-Petersburg State University, Physical Faculty, Optics Department, Saint-Petersburg, Russia 4 October 2005, Saint-Petersburg
Digital high speed CMOS camera pco.1200 hs (PCO.IMAGING) • extremely fast image recording 1GB/s, • high resolution (1280x1024 pixel), • - exposure time range 1 μs-5 s, • - image memory in camera • (camRAM up to 4 GB), • - interframing time 75 ns, • - standard interface. The resolution 1280x1024 pixel enables to make about 500-600 frames per second (fps) that is not suitable for the study of the plasma in question. Coupling the camera with a spectrograph enables us to use the camera with the lowest number of pixels in vertical direction produced by PCO.IMAGING: 1280x16 pixel. This makes it possible to increase the number of frames per second till about 40 000. The number of points during a Tokamak current pulse with the duration ~ 1 ms could reach ~ 40. - pixel size – 12μm x 12μm, - full well capacity – 63 000 e-, - peak quantum efficiency (520 nm) – 27%, - dynamic range – 59.6 db, - readout noise – 85 e-rms, - pixel scan rate – 66/86 MHz, - spectral range – (290-1100) nm, - dark current – 5900 e-/pixel-s.
Objective NIKON AF-S DX Zoom-Nikkor ED corrected spherical and chromatic aberration - focal length: 12-24 mm, - maximum aperture: f/4, - lens construction: 11 elements in 7 groups (3 aspherical lens and 2 ED (extra-low dispersion) lens elements), - picture angle: (99-61)o, - closest focus distance: 0.3 m
Monochromator / Spectrograph SP-2358 internal image correction with original polished aspheric optics, triple grating turret, stepping motor scanning system with 32-bit microprocessor control, RS 232 and USB computer interfaces, scan control software for Windows. Three gratings are chosen so that all needed spectral regions can be investigated
Monochromator / Spectrograph SP-2358 Gratings Spectrograph SP-2358 one usual exit slit temporal scan of any wavelength gap 300mm focal length, f/4 imaging monochromator/spectrograph with one micrometer controlled entrance slit, fixed entrance diverter mirror, one micrometer controlled side exit slit, motorized exit diverter mirror and multichannel detector flange in end position
Experimental set-up I. Usage of camera for plasma observation in visible region II. Diagnostic system to measure spectra
Scientific problems that can be solved with the help of the spectroscopic diagnostic complex • Monitoring the Tokamak plasma parameters to influence on its operation. This task is very important, because such problems are possibly identical for all types of Tokamaks. • Study of Tokamak plasma near walls where plasma reacts with wall material. • Study of different materials introducing into Tokamak camera. These materials can be in gas phase – investigation of hot plasma of different composition, – and in solid state – investigation of interaction between plasma and solid bodies. • Developing diagnostics methods. • 5. Teaching young scientists and engineers to operate with Tokamak and hot plasma and carry out its diagnostics.