Feasibility study of a heterodyne radiometer for ece measurements on FTU
Here is presented a study for the feasibility of a heterodyne radiometer for temperature measurements on FTU by means of electron cyclotron emission, that will cooperate with the grating polychromator during the experiments of RF heating at 140 GHz. The system has been designed to measure the plasma temperature at 24 different radial positions with a spatial resolution less than 1 cm and a time resolution up to 10 ms. The channel frequency range is from 116 GHz to 164 GHz, that allows measurements with two different toroidal magnetic fields : at 50 kG, using the emission at the fundamental cyclotron frequency in the ordinary mode and at 25 kG using the second harmonic in the extraordinary mode. It is also presented a study of the density range where measuremnts are possible, of the optical thickness and of the harmonic overlap. The diffraction effects on the quasi-optical components of the radiation collecting system has been studied and results are also presented here. The signal-to-noise ratio of the radiometer is about 450 for a time resolution of 0.1 ms. An absolute calibration of the system can be performed.
Bibliographic Reference: Report: RT/ERG/FUS/95/14 (1995) 20pp.
Availability: Available from Servizio Edizioni Scientifiche, ENEA Centro Ricerche Frascati, CP 65, 00044, Frascati, Roma (IT)
ISBN: ISSN 1120-5563
Record Number: 199610996 / Last updated on: 1996-09-30
Original language: en
Available languages: en