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Improvement of Infrared Imaging Video Bolometer Systems in LHD

Kiyofumi MUKAI, Byron J. PETERSON, Shwetang N. PANDYA¹⁾, Ryuichi SANO¹⁾ and Muneji ITOMI²⁾

National Institute for Fusion Science, Toki 509-5292, Japan

1)

The Graduate University for Advanced Studies, Toki 509-5292, Japan

2)

Graduate School of Engineering Hokkaido University, Sapporo 060-8628, Japan

(Received 10 December 2013 / Accepted 19 February 2014 / Published 7 May 2014)

Abstract

The InfraRed imaging Video Bolometer (IRVB) is a powerful diagnostic to measure a plasma radiation profile especially for three-dimensional measurements. An IRVB mainly consists of a pinhole camera section and an IR camera section. The plasma radiation profile is projected on a thin metal foil through an aperture in the pinhole camera resulting in a two-dimensional temperature distribution. Then, the distribution is observed from the back side by an IR camera as an IR image. Since the image contains the effects of heat diffusion, a calibration of the heat characteristics of the foil is needed to obtain the radiation profile by solving the two-dimensional heat diffusion equation. Some deposition was observed on the foil in the Large Helical Device (LHD) plasma experiment. The effect of this on the heat characteristics of the foil should be studied although it can be compensated for by the calibration. Currently four IRVBs are operating in LHD to investigate the radiation collapse and plasma detachment phenomena. The sensitivities of IRVBs at the 6.5-L and 10-O ports were improved from the experimental campaign in FY 2013 by replacing the IR cameras of these ports. The sensitivity at the 6.5-U port was also improved by applying the periscope system.

Copyright (c) 2014 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

bolometer, imaging, IRVB, radiation measurement, LHD, radiation collapse, plasma detachment

DOI: 10.1585/pfr.9.3402037

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References

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This paper may be cited as follows:

Kiyofumi MUKAI, Byron J. PETERSON, Shwetang N. PANDYA, Ryuichi SANO and Muneji ITOMI, Plasma Fusion Res. 9, 3402037 (2014).