The 14-channel grating polychromator for ECE measurements in LHD

K. Kawahata, P. C. DeVries, Y. Nagayama, S. Inagaki, T. Tokuzawa, K. Tanaka, H. Sasao

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Abstract

A 14-channel grating polychromator for the purpose of measuring the electron cyclotron emission (ECE) spectrum has been developed and installed on the large helical device (LHD). The grating polychromator has a Czerny-Turner setup. The main advantage of the grating polychromator is that it has a broad spectral range. Hence, it can be utilized at different magnetic field strengths. Changing the angle or replacing the grating can do this. Gratings with a grid constant of d = 2.3, 3, and 5 mm and a blaze angle of 20° can be applied and the scattered spectrum is directed to 14-liquid He cooled InSb detectors. Standard operation is performed with d = 3 mm, frange= 148-105GHz. This is second harmonic ECE for B = 2.75 T. Each channel has a spectral resolution of Δf (full width at half maximum) = 2.6 GHz or f/Δf=60 at f = 150GHz. The properties of the instrument and first experimental results of LHD ECE will be described in this article.

Original languageEnglish
Pages (from-to)387-390
Number of pages4
JournalReview of Scientific Instruments
Volume72
Issue number1 II
DOIs
Publication statusPublished - Jan 1 2001

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All Science Journal Classification (ASJC) codes

  • Instrumentation

Cite this

Kawahata, K., DeVries, P. C., Nagayama, Y., Inagaki, S., Tokuzawa, T., Tanaka, K., & Sasao, H. (2001). The 14-channel grating polychromator for ECE measurements in LHD. Review of Scientific Instruments, 72(1 II), 387-390. https://doi.org/10.1063/1.1309006