Abstract
Fiber Bragg gratings (FBGs) are valuable dosimeters for doses up to 100 kilograys (kGy), but have hardly been used for the low-dose range of a few grays (Gy) required in medical radiation dosimetry. We report that embedding a doped silica fiber FBG in a polymer material allows a minimum detectable dose of 0.3 Gy for -radiation. Comparing the detector response for different doped silica fibers with various core doping, we obtain an independent response, in opposition to what is reported for high-dose range. We hypothesized that the sensor detection is based on the radio-induced thermal expansion of the surrounding polymer. Hence, we used a simple physical model based on the thermal and mechanical properties of the surrounding polymer and obtained good accordance between measured and calculated values for different compositions and thicknesses. We report that over the 4 embedding polymers tested, polyether ether ketone and polypropylene have respectively the lowest (0.056 pm/Gy) and largest sensitivity (0.087 pm/Gy). Such FBG-based dosimeters have the potential to be distributed along the fiber to allow multipoint detection while having a sub-millimeter size that could prove very useful for low-dose applications, in particular for radiotherapy dosimetry.
Highlights
Fiber Bragg gratings (FBGs) are common in versatile sensors used in a wide range of applications in various industries mainly to measure temperature, stress or pressure since they can be distributed over km range and are invariant to electromagnetic interference
The raw and ambient temperature corrected Bragg wavelength shift (BWS) in terms of time are presented in Figure 4 for a delivered total dose of 20 Gy irradiation using a polymethyl methacrylate (PMMA)
The results presented in this study were unexpected and led us to hypothesize that the measured signal was coming from the effect of the plastic coatings on the FBG
Summary
Fiber Bragg gratings (FBGs) are common in versatile sensors used in a wide range of applications in various industries mainly to measure temperature, stress or pressure since they can be distributed over km range and are invariant to electromagnetic interference. They can be used for instance to detect leaks on a pipeline, or to measure remotely the deformation of the wings of an airplane during flights [1,2]. FBGs sensor has proven to be useful dosimeters in nuclear environment where dose reach up to 100 kGy [5] In these conditions, radiation produces damages to the fiber materials, which modifies the fiber refractive index [6]. This results in a shift of the peak reflectivity wavelength of the FBG that can be monitored with a specialized
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
