A 12-channel heterodyne radiometer system has been developed to obtain electron temperature with high time and spatial resolution from the electron cyclotron emission (ECE) in JT-60U. Resolutions of a single-sideband-type receiver are (1) Δt∼1 μs and (2) Δf=0.5 GHz. The second harmonic extraordinary mode of ECE is utilized for this system and the frequency band is 176-188 GHz. The noise level of the system is determined by unavoidable photon fluctuations, and the signal-to-noise ratio was measured to be about 50 with a video bandwidth of 100 kHz for a signal temperature above ∼200 eV. Details of the design, the obtained performance, and typical measurements are described.
|Number of pages||3|
|Journal||Review of Scientific Instruments|
|Publication status||Published - Dec 1 1995|
All Science Journal Classification (ASJC) codes