A new magnetic configuration for a small in-plane electromagnetic acoustic transducer applied to laser-ultrasound measurements: Modelling and validation

Abstract This paper presents an enhanced in-plane electromagnetic acoustic transducer (EMAT) for detecting laser-generated ultrasound. Instead of using post-processing of numerical data to enhance signal-to-noise, the paper describes a new EMAT design to increase the magnetic flux density applied to the sample. The EMAT's magnetic flux density was modelled in 3D using a finite element software to predict new magnetic spatial field distributions. A configuration was found to increase the flux density by a factor of 1.8 ± 0.2, compared to magnetic configurations previously used in conventional designs. Field predictions were implemented and confirmed experimentally. As a consequence, laser-ultrasound Rayleigh waves have been used to validate the performance of this sensor system. It was found that the EMAT's in-plane sensitivity increased by a factor of 2.0 ± 0.2.

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