Dimensional Measurements Under High Radiation With Optical Fibre Sensors Based on White Light Interferometry - Report on Irradiation Tests

Numerical Analysis of Radiation Effects on Fiber Optic Sensors

“…F-P sensors feature several potential applications for nuclear environments, due to their insensitivity to radiation [14,15,34].…”

“…It is necessary to consider the radiation-induced length change to observe how RIC affects the designed F-P sensor, even though the cavity medium is air. For simulation purposes, we considered a roughly 50-µm-long fiber segment exposed to radiation beyond the fixing point, for example, as in [15], and compaction was calculated for that length. The responses of the sensor can differ, depending on the choice of cavity length as well as the fiber length exposed to a radiation field.…”

“…The responses of the sensor can differ, depending on the choice of cavity length as well as the fiber length exposed to a radiation field. For example, F-P sensors with different lengths of lead-in fibers were intentionally exposed to radiation, and compaction was assessed on the fiber tips in [15]. The calculated length change taken from Table 2 was used to simulate the F-P sensor.…”

“…However, an in-depth understanding of how radiation affects optical fibers and optical fiber sensors (OFS) is required to ensure their reliability and survivability. Early work has shown that three types of resonance-based OFS-fiber Bragg grating (FBG), long-period grating (LPG), and Fabry-Perot (F-P)-have been widely tested in nuclear environments [8][9][10][11][12][13][14][15]. Studies show that the survivability and performance of OFS in nuclear environments largely depends on the chemical composition of the fibers, the nature of the irradiation, the manufacturing conditions, and the wavelength of light used [3,16].…”

Nuclear instrumentation and measurement: a review based on the ANIMMA conferences

“…But the fiber under radiation is also subject to compaction and this effect leads to a temporal drift of the conventional EFPI. A first prototype [202] with two fixed points and radhard fiber has been designed and irradiated in the SMIRNOV facility of SCK•CEN for 27 days at around 120°C and under a gamma dose rate of 7.2 MGy/h and a neutron flux of 1.2 Â 10 13 n fast /(cm 2 s). The results show that fiber extensometers under fast neutron fluences are possible with a careful design and an improved prototype was tested in SMIRNOV in 2013 but now at temperatures between 200 and 395°C [202].…”