In-core high temperature measurement using fiber-Bragg gratings for nuclear reactors

Villiers, Gerrit J. de; Treurnicht, Johan; Dobson, Robert T.

doi:10.1016/j.applthermaleng.2012.01.024

Cited by 27 publications

(15 citation statements)

References 4 publications

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“…26 Although apodization technique is used widely in different FBG applications, 27,28 few literature reviews deal with optimizing temperature sensor performance using apodization technique. 20,22,29,30 In this work, we demonstrate the effect of different apodization profiles (Uniform, Gaussian, Hamming, Barthann, New apodization function, and Nuttall) on temperature sensor FBG-based. Reasons for choosing those apodization functions are due to their distinctive qualities.…”

Section: Introductionmentioning

confidence: 99%

“…20 Reducing or eliminating the sidelobes will result in higher SNR and avoid the possible confusion of a sidelobe with an FBG peak.…”

Section: Introductionmentioning

confidence: 99%

“…Not to mention, the ease with which spectral information can be demultiplexed allows the value of each FBG temperature sensor to be extracted as a function of position along the length of the fiber. 20 Distributed sensors are particularly attractive for use in applications where monitoring of the temperature is required at a large number of points or continuously over the path of the fiber. Typical examples of applications areas are temperature profiling in electrical power transformers, generators, reactor systems, process control systems and fire detection systems.…”

Section: Introductionmentioning

confidence: 99%

“…Also, the small size and weight and the great flexibility that allow access to restricted areas made FBG temperature sensors attractive for many applications. 20,21 For good and efficient temperature sensor, the broad spectral response can result in poor sensitivity and hence should be avoided. 22 High reflectivity, low sidelobes, narrow FWHM and high sensitivity should be obtained.…”

Section: Introductionmentioning

confidence: 99%

“…These values are chosen to meet previous literature reviews. 3,20,[31][32][33] Table I is the apodization functions' specifications. The Rectangular window has the highest magnitude and the lowest mainlobe width but with high leakage factor and low relative low sidelobe attenuation.…”

Section: A Introductionmentioning

confidence: 99%

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Performance optimization of apodized FBG-based temperature sensors in single and quasi-distributed DWDM systems with new and different apodization profiles

2013

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In this work, different FBG temperature sensors are designed and evaluated with various apodization profiles. Evaluation is done under a wide range of controlling design parameters like sensor length and refractive index modulation amplitude, targeting a remarkable temperature sensing performance. New judgment techniques are introduced such as apodization window roll-off rate, asymptotic sidelobe (SL) decay level, number of SLs, and average SL level (SLav). Evaluation techniques like reflectivity, Full width at Half Maximum (FWHM), and Sidelobe Suppression Ratio (SLSR) are also used. A “New” apodization function is proposed, which achieves better performance like asymptotic decay of 18.4 dB/nm, high SLSR of 60 dB, high channel isolation of 57.9 dB, and narrow FWHM less than 0.15 nm. For a single accurate temperature sensor measurement in extensive noisy environment, optimum results are obtained by the Nuttall apodization profile and the new apodization function, which have remarkable SLSR. For a quasi-distributed FBG temperature sensor the Barthann and the new apodization profiles obtain optimum results. Barthann achieves a high asymptotic decay of 40 dB/nm, a narrow FWHM (less than 25 GHZ), a very low SLav of −45.3 dB, high isolation of 44.6 dB, and a high SLSR of 35 dB. The new apodization function achieves narrow FWHM of 0.177 nm, very low SL of −60.1, very low SLav of −63.6 dB, and very high SLSR of −57.7 dB. A study is performed on including an unapodized sensor among apodized sensors in a quasi-distributed sensing system. Finally, an isolation examination is performed on all the discussed apodizations and a linear relation between temperature and the Bragg wavelength shift is observed experimentally and matched with the simulated results.

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