A fast-scanning heterodyne radiometer for electron cyclotron emission measurements in HT-7 superconducting tokamak

Citation
Sy. Zhang et al., A fast-scanning heterodyne radiometer for electron cyclotron emission measurements in HT-7 superconducting tokamak, REV SCI INS, 71(5), 2000, pp. 2058-2061
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences","Instrumentation & Measurement
Journal title
REVIEW OF SCIENTIFIC INSTRUMENTS
ISSN journal
0034-6748 → ACNP
Volume
71
Issue
5
Year of publication
2000
Pages
2058 - 2061
Database
ISI
SICI code
0034-6748(200005)71:5<2058:AFHRFE>2.0.ZU;2-G
Abstract
A fast-scanning heterodyne radiometer employing a backward-wave oscillator (BWO) in 78-118 GHz was developed and installed for electron cyclotron emis sion (ECE) measurements in HT-7 superconducting tokamak. The radiometer mea sures 16 ECE frequency points with a scanning time period of 0.65 ms, each of the frequency points can be preset by the program to meet specific inter ests in physics. The high scanning speed is achieved by carefully choosing a BWO, very finely adjusting the radiometer over the full waveband, and by eliminating some elements that are routinely included in a fast-scanning ra diometer system. A horizontal view of the ECE optics was installed to measu re electron temperature profiles. The spatial resolution is about 1 cm (B-t =2 T) in the center of the HT-7 minor cross section, determined by the inte rmediate frequency of 0.1-0.5 GHz in the radiometer. Vertically viewing opt ics along a perpendicular chord was also installed to study nonthermal ECE spectra. Preliminary measurement results in pellet injection plasma and low er-hybrid current drive plasma were presented. (C) 2000 American Institute of Physics. [S0034-6748(00)00705-X].