Plasma and Fusion Research

Volume 14, 1402128 (2019)

Regular Articles

Fast Tangentially Viewed Soft X-Ray Imaging System Based on Image Intensifier with Microchannel Plate Detector on QUEST

Canbin HUANG, Kazuaki HANADA¹⁾, Kengoh KURODA¹⁾, Shinichro KOJIMA¹⁾, Hiroaki FUJIYOSHI¹⁾, Hiroki MIURA¹⁾, Tomoki YAMADA¹⁾, Hiroshi IDEI¹⁾, Makoto HASEGAWA¹⁾ and Takumi ONCHI¹⁾

: Interdisciplinary Graduate School of Engineering and Sciences, Kyushu University, Kasuga 812-8580, Japan
1): Research Institute for Applied Mechanics, Kyushu University, Kasuga 812-8580, Japan

(Received 15 April 2019 / Accepted 11 June 2019 / Published 24 July 2019)

Abstract

A two-dimensional (2D) soft X-ray (SXR) imaging system for obtaining tangential views of plasma-produced SXR has been installed on the QUEST tokamak. The system comprises a chevron micro-channel plate (MCP) and a phosphor screen, which together serve as an SXR detector and image intensifier, along with a high-speed video camera for capturing and storing image data. The system can be used in imaging mode to obtain high spatial- and time-resolution images or in photon counting mode at an ultra-high framing rate of 100 kHz to obtain SXR energy spectra. Here, we propose a method of in situ energy calibration based on the transmission characteristics of a 25-μm Be filter. The proposed method was used to obtain SXR spectra in the energy range 1.5 - 3.5 keV with a core electron temperature in agreement with electron temperatures measured by the Thomson scattering method. Furthermore, oscillations based on the modification of plasma parameters and rapid increases in impurity radiation were detected in imaging mode. This dual-mode-compatible method for obtaining 2D SXR diagnostics is useful for the study of high temperature plasmas.

Keywords

soft X-ray imaging, MCP, photon counting

DOI: 10.1585/pfr.14.1402128

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