Boonsang, Siridech
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Preferred name
Boonsang, Siridech
Alternative Name
Boonsang, S.
Main Affiliation
Email
siridech.bo@kmitl.ac.th
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Item type:Publication, A new magnetic configuration for a small in-plane electromagnetic acoustic transducer applied to laser-ultrasound measurements: Modelling and validation(2006-01-10); Dewhurst, R. J.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. © 2005 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, A sensitive electromagnetic acoustic transducer for picometer-scale ultrasonic displacement measurements(2006-03-13); Dewhurst, R. J.The paper presents a novel design of an electromagnetic acoustic transducer (EMAT) for non-contact ultrasonic measurements. An EMAT sensor has been miniaturized with an overall receiver size to 1.0 cm diameter. It has been combined with a specially designed low noise preamplifier. Calibration procedures with a Michelson interferometer revealed that the EMAT sensor detected small displacement amplitudes as low as 1.0 ± 0.2 pm in aluminium samples, with a signal bandwidth up to 7.5 MHz (-3 dB). Alternatively, the sensitivity figure can be expressed in terms of a noise-equivalent displacement spectrum as 4.2 × 10 <sup>-17</sup> mHz <sup>-1/2</sup>. The absolute sensitivity of the EMAT was 1.98 ± 0.50 V pm <sup>-1</sup> for the detection of longitudinal ultrasonic waves. This sensitivity is compared with other forms of ultrasonic transducer. © 2005 Elsevier B.V. All rights reserved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Modelling of magnetic fields to enhance the performance of an in-plane EMAT for laser-generated ultrasound(2006-12-22); Dewhurst, R. J.A new magnetic arrangement is described for use with an in-plane electromagnetic acoustic transducer (EMAT) for detecting laser-generated ultrasound. The magnetic flux density was modelled and validated. Modelling was accomplished in 3D using finite element software to predict new magnet spatial distributions. A configuration was found which increased the magnetic flux density by a factor of 1.8 ± 0.2, compared to magnetic configurations previously used in conventional designs. Model predictions were implemented and confirmed experimentally. As a result, laser ultrasound Rayleigh waves have been used to verify the performance of this sensor system. It was establish that the EMAT's in-plane sensitivity increased, while the frequency bandwidth improvement factor was about 1.9 ± 0.2. The resonant frequency increased from 6.5 MHz and 16.4 MHz, with both exhibiting an extended frequency response well beyond the resonant values. For maximum frequency response, it was demonstrated that added elements such as cables may have a deleterious effect. In particular the length of the cable, which in turn adds capacitance to the overall circuit, will decrease the frequency response of the EMAT. The frequency response was compared with a previous sensor, to provide an increased resonant frequency factor of 2.5 ± 0.2. © 2006 Elsevier B.V. All rights reserved.