No abstract

The refractivities of sulphur hexafluoride and thionyl fluoride have been measured at wavelengths of 632.99 and 1300 nm using a polarization interferometer. The value obtained for at 632.99 nm is in close agreement with results of previous workers, which gives credence to the new values for at 1300 nm and for at both wavelengths. is produced in electrical discharges through as a consequence of dissociation and these refractivity data may find an application in the interferometric monitoring of gas degradation in discharges.

An optical fiber sensor for electric field and electric charge, based on the deflection of a small cantilever, has been developed. When the sensor head is placed in an electric field, induced charging produces deflection of the cantilever, which is measured using low-coherence, Fabry-Perot interferometry. The sensor has been used to measure the electric field in the vicinity of a Van de Graaff generator, in the range 135-650 V/cm. The measured deflections are in good agreement with the predictions of a simple model equating the electrostatic and mechanical forces acting on the cantilever.

No abstract

Sulphur hexafluoride ( SF 6) is used as an insulator in high-voltage systems. An electrical breakdown dissociates ( SF 6). Therefore, the insulating efficiency is degraded. If the ( SF 6) is not renewed, failure of the system can occur. A monitoring device for ( SF 6) loss is required, and an optical fiber sensor for continuous monitoring of ( SF 6) degradation in high-voltage switchgear has been developed. Dissociation products of the ( SF 6) discharge include HF and atomic F, both of which react readily with silica. This reactivity is utilized in our sensor, where etching of a glass fiber surface modifies the transmission characteristics of the fiber.