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Metrological Characterization of a High-Temperature Hybrid Sensor Using Thermal Radiation and Calibrated Sapphire Fiber Bragg Grating for Process Monitoring in Harsh Environments
| Content Provider | MDPI |
|---|---|
| Author | Eisermann, René Krenek, Stephan Habisreuther, Tobias Ederer, Petra Simonsen, Sigurd Mathisen, Helge Elsmann, Tino Edler, Frank Schmid, Daniel Lorenz, Adrian Olsen, Åge Andreas Falnes |
| Copyright Year | 2022 |
| Abstract | Fiber Bragg gratings inscribed in single crystalline multimode sapphire fibers (S-FBG) are suitable for monitoring applications in harsh environments up to 1900 °C. Despite many approaches to optimize the S-FBG sensor, a metrological investigation of the achievable temperature uncertainties is still missing. In this paper, we developed a hybrid optical temperature sensor using S-FBG and thermal radiation signals. In addition, the sensor also includes a thermocouple for reference and process control during a field test. We analyzed the influence of the thermal gradient and hotspot position along the sensor for all three detection methods using an industrial draw tower and fixed point cells. Moreover, the signal processing of the reflected S-FBG spectrum was investigated and enhanced to determine the reachable measurement repeatability and uncertainty. For that purpose, we developed an analytical expression for the long-wavelength edge of the peak. Our findings show a higher stability against mechanical-caused mode variations for this method to measure the wavelength shift compared to established methods. Additionally, our approach offers a high robustness against aging effects caused by high-temperature processes (above 1700 °C) or harsh environments. Using temperature-fixed points, directly traceable to the International System of Units, we calibrated the S-FBG and thermocouple of the hybrid sensor, including the corresponding uncertainty budgets. Within the scope of an over 3-weeks-long field trial, 25 production cycles of an industrial silicon manufacturing process with temperatures up to 1600 °C were monitored with over 100,000 single measurements. The absolute calibrated thermocouple ( |
| Starting Page | 1034 |
| e-ISSN | 14248220 |
| DOI | 10.3390/s22031034 |
| Journal | Sensors |
| Issue Number | 3 |
| Volume Number | 22 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2022-01-28 |
| Access Restriction | Open |
| Subject Keyword | Sensors Nuclear Energy and Engineering Telecommunications High-temperature Sensor Fiber Bragg Grating (fbg) Sapphire Fiber Harsh Environment |
| Content Type | Text |
| Resource Type | Article |
