Radiation-hard KS-4V glass and optical fiber, manufactured on its basis, for plasma diagnostics in iter

Transmission spectra and optical losses before and after gamma-irradiation (Co-60) at a dose up to 11 MGy in 1 cm thick glass plates and in "all-silica" type optical fibers were examined. KS-4V, KU-1, KUVI, Suprasil F-300 glasses and fluorine-doped glass (vapor-phase axial deposition (VAD) technology, Japan) were used as a core material in the fibers. Comparison tests of four types of high purity fused silica (HPFS) showed that the highest ORR is characteristic of KS-4V (the lowest chlorine content). Optical Radiation Resistance (ORR) testing of "all-silica" type fibers (KS-4V glass, Japan VAD glass, Suprasil F-300 and KU-1 glasses as a core material) showed that the highest ORR is characteristic of KS-4V glass, which contains minimum of impurities. The level of optical losses in the visible band of the KS-4V spectrum is twice lower than the level of fluorinated glass (VAD), and 4-5 times lower as the level of losses of Suprasil F-300 and KU-1 respectively.