Fiber-optical probes to measure megampere currents and megagauss magnetic fields in conditions of high-power radiation effect

The paper presents optical probes to measure currents of tens megamperes and megagauss magnetic fields of ~10 MGs. Operating principle of the probes is based on the Faraday effect. Investigation results on determination of optical losses appearing at fibers alloyed with different dopants in a core under influence of an ionizing radiation at its rise time up to 10¹³ Rs are described in the paper. The least optical losses have been observed in the fibers of POD type. The core of this fiber is made of pure quartz, and the shell is alloyed with fluorine. Optical spectrum range of the least optical losses is ~(1.0...1.3) μm. We did not observe light depolarization at radiation effect on the POD type fiber with small LB (low-birefringence), i.e. general light intensity attenuation without disturbance of its linear polarization takes place. Such fiber could be used as the optical probes to record the currents of tens megamperes at rise time of ≤ 100 ns in the conditions of radiation influence on the fiber with exposition dose increase rate up to 10¹³ R/s.