A new detection method used to calibrate Fabry-Perot interferometers in the infrared range
Fabry-Perot interferometers are used routinely in the Tore Supra tokamak in order to measure the time evolution of the electron temperature of the confined plasmas. Calibration of such interferometers requires the detection of very low DC levels (0.1 nV) with signal-to-noise ratios less than 1.0 x E-5, which is generally not compatible with standard detection methods. A new correlation method to achieve this absolute calibration is proposed. It is based on a proper noise auto-correlation technique combined with an optimised signal filtering involving Fourier analysis. The advantages of the method are detailed and compared experimentally to standard averaging techniques, such as coherent addition and synchronous detection. The method can be used in a more general context every time very small amplitude signals are to be measured.
Bibliographic Reference: Report: EUR-CEA-FC-1490 EN (1993) 23 pp.
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199311124 / Last updated on: 1994-11-29
Original language: en
Available languages: en