X-ray sensor based on a plastic optical fiber for monitoring high voltage interrupters

An x-ray sensor based on a fluorescent plastic optical fiber is described. The core is doped with an organic fluor while double cladding contains an inorganic product (ZnS) converting x-ray energy into visible light. The light emitted by the sensor is guided by a commercial PMMA fiber to a photodiode whose signal is amplified. The electronics have been optimized to increase sensitivity and reduce noise. The paper indicates the methods used to prepare fibers. It describes their characterization and gives the main characteristics of the amplifier. The sensor is used to visualize the x-rays emitted by vacuum interrupters during switching. Signal modification gives us information on the surface degradation of the electrodes. Among other advantages, the sensor can be used on site, without disconnecting the interrupter. (C) 1996 American Institute of Physics.