Dose rate effect on radiation induced attenuation of pure silica core optical fibres

“…Pure Silica core fibers for example, are known to be relatively resistant to radiation [5]. Unfortunately, they also have a strong dose rate dependency making them most likely unsuitable for radiation sensing in environments with altering conditions [6].…”

Section: Icso 2014mentioning

confidence: 99%

First steps towards a distributed optical fiber radiation sensing system

Toccafondo

Brügger

Pasquale

et al. 2017

International Conference on Space Optics — ICSO 2014

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Ionizing radiations affect installed electronics, limit equipment lifetimes and eventually alter materials both in space applications as well as high energy accelerators and physics experiments. In order to monitor radiation levels and predict equipment and material lifetimes, an accurate radiation dosimetry is highly important and very challenging often due to two main reasons: (i) large areas and (ii) extended dose range of interest. In this respect a radiation sensor based on a distributed optical fiber sensing system could be a promising solution. Such sensor systems are immune to electromagnetic field interference, have a light weight and small size making them suitable for a large number of applications including possible future space missions. In addition, optical fiber sensors have reached a very high accuracy in measuring physical quantities as a function of distance very accurately with metre or sub-metre-scale spatial resolutions. Their distributed nature in fact, is particularly suitable for real-time monitoring of long distances as particles accelerator tunnels like the one of the Large Hadron Collider (LHC) or large space stations as the International Space Station (ISS) which, to the best of our knowledge, only holds punctual radiation sensors as passive radiation dosimeters (PRD) among many others. The first step of the feasibility study of a distributed optical fiber radiation sensing system consists in characterizing and selecting the most suitable optical fiber which represents the sensing mean of the system. The effect of ionizing radiation on optical fibers has been well documented in literature and already several decades ago it was known that an irradiated fiber will suffer from radiation induced attenuation (RIA). Depending on the fiber’s type and composition the RIA shows varying response to total dose, dose rate, temperature, wavelength and light power. In the case of P-doped fibers, the radiation response is independent from the dose rate the fiber is exposed to, which makes it suitable for sensing a wide range of different radiation environments. Moreover, P-doped fibers have a low annealing behavior and their RIA doesn’t show any strong temperature dependence for room temperature environments. All the above mentioned parameters affecting the RIA are important in order to fully characterize fiber candidates to be used for dosimetry and will be detailed in the next section. Based on the above considerations, in this paper we investigate the response to ionizing radiation of three different P-doped optical fibers which could be suitable candidates for the radiation sensing system. Two of the fibers were single mode (SM) and the RIA has been studied at 1312 nm and 1570 nm as a function of the total dose up to about 18 kGy and with a dose rate of 46.7 mGy/s in one case and almost 60 kGy at 153 mGy/s in the other. The third fiber which was a multimode (MM) one has been tested at 830 nm and 1312 nm and has been irradiated with dose rates ranging from 0.5 mGy/s up to almost 1.7 Gy/s reaching ...

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“…Most of the research targeted communication report on optical fibers for remote control of experiments or for data transfer in radiation environments. The irradiation effects were evaluated as function of the dose rate or total dose [1,2]. Spectral measurements were done on-line or off-line, mostly in the visible and near IR range, under gamma-ray, X-ray or neutron irradiation [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Investigation of UV optical fibers under synchrotron irradiation

Sporea¹,

Mihai²,

Sporea³

et al. 2014

Opt. Express

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Abstract:The focus of the present paper deals, for the first time, with commercial UV optical fibers, characterizing their behaviour as they are subjected to very high flux wiggler generated synchrotron radiation. Five distinct types of UV optical fibers, produced by three manufactures, were exposed to total doses between 5 Gy and 2000 Gy. The exposure to synchrotron radiation was performed in two campaigns. The tests were run off-line and considered the dependence of the radiation induced attenuation (RIA) as function of the total dose. The recovery of the radiation induced colour centres was studied at room temperature and after heating the samples up to 560 K. As a première, we also investigated through THz imaging and spectroscopy the irradiated optical fiber samples. Under these conditions, three of the optical fibers proved to be radiation resistant. The two optical fibers sensitive to synchrotron radiation exhibited a linear variation of the optical absorption at the wavelengths of λ = 229 nm, λ = 248 nm, and λ = 265 nm, for total doses between 60 Gy and 2000 Gy. These two samples showed also an increase of the optical absorption in the UV spectral range when heated to 560 K. The optical fibers sensitive to synchrotron radiation can potentially be used for on-line radiation dosimetry. ©2014 Optical Society of America

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Dose rate effect on radiation induced attenuation of pure silica core optical fibres

Cited by 35 publications

References 7 publications

Performance of optical fibers in space radiation environment

Performance of optical fibers in space radiation environment

First steps towards a distributed optical fiber radiation sensing system

Investigation of UV optical fibers under synchrotron irradiation

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