A double pass rapid scanning Fourier transform spectrometer for plasma diagnostics

The construction and the performance of a double pass rapid scanning Fourier transform spectrometer are described. The instrument covers a frequency range below 900 GHz. It has a maximum spectral resolution of 6.6 GHz and a maximum time resolution of 10 msec. The spectrometer has been applied to JIPP T-II device at Institute of Plasma Physics in Nagoya University. Electron cyclotron emission from the device has been measured and the electron temperature of the plasma has been obtained. The results are shown.