Schematic illustration of distributed radiation leak detection using fibre optic radiation sensor

Schematic illustration of distributed radiation leak detection using fibre optic radiation sensor

Source: BAM, Division Fibre Optic Sensors

Considerable attention has been paid to the development of optical fibre radiation detectors and dosimeters over the last decades. Optical fibre sensors possess number of advantageous characteristics such as low weight, compactness, electromagnetic immunity and passivity. Especially the possibility of remote and real-time measurement over optical fibre is attractive for radiation monitoring. In addition, optical fibre sensors offer a unique advantage of spatially distributed sensing along the whole fibre length, which is not accessible with any other technology. A single optical fibre can replace a number of point sensors and provide spatially- and temporally-continuous monitoring over long distances. Distributed fibre optic radiation sensors are therefore attractive especially for monitoring of extensive areas, e.g. for radiation leak detection in radioactive waste repositories, nuclear power plants or particle accelerator beamlines.

Majority of the research has been so far focused on the more mature glass optical fibres. Only more recently, also possibility of radiation monitoring with “younger” polymer optical fibres has been explored. In the field of radiation sensing, polymer materials are well-known from the use in plastic sheet dosimeters. Thanks to the good reliability and stability, plastic sheet dosimeters are one of the most widely used dosimetry techniques. Polymer optical fibre-based radiation sensor can thus combine advantageous dosimetry properties of polymers and unique characteristics of fibre optic sensors. In comparison to glass optical fibres, polymer fibres are typically more flexible, robust, easy to handle and considerably cheaper. Therefore, off-the-shelf polymer optical fibres might be especially interesting as user-friendly cheap disposable sensors for radiation sensing. Due to better biocompatibility, polymer optical fibres are generally more acceptable for medical use and polymer optical fibre dosimeters might hold potential even for in vivo radiotherapy applications.

In this work, radiation response of highly-sensitive commercial perfluorinated polymer optical fibres was characterized with regard to their use for radiation monitoring. Due to the advantageous properties of the fibres, the proposed approach can yield dose measurement with sub-gray resolution and accuracy. In addition, possibility of distributed low dose radiation detection with polymer optical fibre has been demonstrated for the first time.

Radiation-induced attenuation of perfluorinated polymer optical fibres for radiation monitoring
Pavol Stajanca, Katerina Krebber
Sensors. 2017 Sep; 17(9): 1959.
BAM Department Non-Destructive Testing, Division Fibre Optic Sensors