Real-time fringe correction algorithm for the JET interferometer
On the JET facility, the line-integrated electron density is measured by a multi-channel far-infrared (FIR) interferometer. The basic source of radiation is a deuterium cyanide laser (15195mm) measuring the density along four vertical and four nearly horizontal (lateral) channels. During high-density discharges the system suffers from fringe jumps that are manually partially corrected by an off-line program. This intermittent phenomenon prevents reliable usage of the measured line-integrated density in a real-time feedback controller. To solve this problem we have developed a method to correct the fringe jumps on the lateral channels in real time. The method uses the additional methyl alcohol laser (15118.8mm) interferometer present on the lateral channels to compensate the vibrations. The method has been successfully tested with off-line test data, before implementation on a VERSA Module Eurocard system for the real-time control of the JET discharges.
Bibliographic Reference: An article published in:Review of Scientific Instruments, vol.74 no.8 (2003) pp.3645-3652
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1063/1.1593810
Record Number: 200316832 / Last updated on: 2003-10-08
Original language: en
Available languages: en