Fiber-optic dosimeter based on radiation-induced attenuation in P-doped fiber: suppression of post-irradiation fading by using two working wavelengths in visible range

Abstract

The design of a fiber-optic dosimeter, which determines the radiation dose from the difference of radiation-induced attenuation (RIA) Δα measured in a P-doped silica fiber at λ = 413 and 470 nm, is presented along with its first test results under gamma-radiation (dose rates 0.00064 and 0.0066 Gy/s, maximal dose ~2Gy). The dose-dependence of Δα as well as of RIA at individual wavelengths is found to be well described by a power law, the exponent lying in the range 0.90-0.94. In contrast to RIA at individual wavelengths, Δα is found not to depend on dose rate and to decay only slightly on termination of irradiation. Therefore, using Δα for dosimetry is argued to be more promising.

Combined Temperature Radiation Effects and Influence of Drawing Conditions on Phosphorous‐Doped Optical Fibers

“…[9,[12][13][14] In fact, a fiber-based dosimeter could rely on the measurement of the RIA in the OF in the visible domain at one or more wavelengths. [15] We carried out the EPR measurements related to this study a few weeks after the irradiation. Some of the RIA tests we performed evidenced that after the irradiation the OF experienced a partial recovery of the radiation induced losses, therefore the paramagnetic defects detected by EPR are considered to be the stable ones, which are leftover by the recovery processes.…”

“…[9][10][11] Therefore, several authors have proposed to exploit such property for the fabrication of OFs radiation sensors or dosimeters. [12][13][14][15][16] Despite the technological interests related to P-doped silica and P-doped OFs there are not many literature studies, which are dedicated to this dopant as compared to germanium. In most of the published studies, phosphorus plays the role of a co-dopant and it is therefore difficult to separate its contribution to the optical properties of the material from the ones of the other elements.…”

The use of optical frequency-domain reflectometry in remote distributed measurements of the γ-radiation dose

“…The absorbed dose D dynamics were reconstructed from the radiation induced absorption measurements with the use of the known functional dependence [9]: (1) where coefficients a 1 = 16.7 dB, a 2 = 4.2 dB, a 3 = 7.5 dB, D 1 = 54.7 kGy, D 2 = 2.2 kGy, and D 3 = 9.8 kGy were determined for the calibration curve approxima tion. Figure 2b shows the results of measurements of the absorbed dose at point z 1 = 18.75 m (see Fig.…”

“…The applications of fiber optics in radiation field measurements and monitoring and safety systems of nuclear power facilities are of current importance [1]. The effect of Rayleigh backscattering by frozen in refractive index irregularities of optical fibers is the primary factor that determines the optical signal absorption in the spectral transparency windows of optical fibers and affects the functionality of fiber optic communication lines and fiber optic lasers and sensors [2][3][4][5][6].…”

“…The experiments were performed with the use of an industrial test setup. The measurement principle is based on the detection of radiation induced absorption in phosphor-silicate optical fibers with an increased sensitivity to irradiation [1,9]. The factors affecting the spatial resolution and accuracy of measurements and the limitations of this technology that are related to the induced total losses and a lim ited dynamic range of admissible losses of an OFDR reflectometer are also discussed below.…”