Absolute sensitivity limits of various ultrasonic transducers

Boltz, E. S.; Fortunko, C. M.

doi:10.1109/ultsym.1995.495721

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…However, the potential advantages of improved spatial resolution must be weighed against the decrease in sensitivity. The minimum displacement which may be detected with an interferometric technique, although adequate for many applications, is at least two orders of magnitude greater than that with piezoelectric or capacitive methods Spicer 1987, Boltz andFortunko 1995).…”

Section: Introductionmentioning

confidence: 97%

Determination of the nonlinear ultrasonic parameter using a Michelson interferometer

Hurley

Fortunko

1997

Meas. Sci. Technol.

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We describe an accurate optical technique for determining the nonlinear ultrasonic parameter β. Our technique uses a path-stabilized Michelson laser interferometer, in contrast to more conventional methods which use piezoelectric or capacitive detectors. Features include high spatial resolution (typically 20 µm), flat bandpass response over a wide range (>30 MHz) and simple self-calibration. We demonstrate the technique using a fused silica disc 19.15 mm thick and a fundamental frequency of 10 MHz. For comparison, β was also obtained for the same specimen using capacitive and piezoelectric detectors. Errors and correction factors for all three methods are discussed; in particular, we note the importance of including ultrasonic diffraction effects. When such corrections are applied, we obtain the following results:4 and |β piezo | = 10.2 ± 0.5. These values are in reasonable agreement with each other as well as with published values of |β| = 11-14.

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Section: Introductionmentioning

confidence: 97%

Determination of the nonlinear ultrasonic parameter using a Michelson interferometer

Hurley

Fortunko

1997

Meas. Sci. Technol.

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“…[1][2][3] There are several devices used to generate ultrasonic waves: piezo-electric transducers (PZT), air-coupled transducers, electro-magnetic acoustic transducers (EMAT), and pulsed lasers. [4][5] Laser generation of ultrasound is especially suited for non-contact generation of ultrasound because it efficiently induces all wave modes including Rayleigh, shear vertical, shear horizontal, and longitudinal. A theoretical model for ablative and thermoelastic laser generation of ultrasound has been developed by various researchers.…”

Section: Introductionmentioning

confidence: 99%

Effects of Broadband Laser Generated Ultrasound on Array Gain

Kita

Ume

2006

AIP Conference Proceedings

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The array gain model for laser phased arrays was derived using an assumption that ultrasound from each array source interferes with each other. However, laser generated ultrasound is broad band and ultrasound from each array source may not interfere with each other. A theoretical model called the frequency modulation of phased arrays (FMLPA) was developed and experimentally verified for use when ultrasound from each array member does not interfere with each other. It was experimentally verified that current array gain equations still apply when ultrasound from array members interfere with each other. The FMLPA can be used to create new techniques for measuring weld penetration depth, crack location, and dimensions of objects.

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“…A relatively recent paper by Boltz & Fortunko, discussing how thermal noise limits the performance of conventional microphones, optical interferometers, electromagnetic acoustic transducers (EMATs), and piezoelectric transducers, provides a useful background to the current theoretical investigation (Boltz & Fortunko 1995). Also of interest is Tarnow's paper (Tarnow 1987), which discusses the lower limit of detectable sound pressure for a condenser microphone.…”

Section: Introductionmentioning

confidence: 99%

The minimum signal force detectable in air with a piezoelectric plate transducer

Farlow

Hayward

2001

Proc. R. Soc. Lond. A

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A theoretical analysis based on the Johnson noise equation and an established transducer model has revealed a simple mathematical expression for the minimum signal force detectable in air with an open-circuit piezoelectric plate transducer operating in its thickness mode. A significant finding is that, except for any frequency dependence associated with a transducer's intrinsic losses, the minimum detectable signal force is independent of frequency. By contrast, the sensitivity (e.g. volts per unit signal force) is known to be a strong function of frequency, with the principal peak being at the plate's fundamental thickness resonance. The results are explained by showing that the new equation for minimum detectable force (MDF) is equivalent to the mechanical version of the Johnson noise equation. Both the Johnson noise equation and its mechanical equivalent are consistent with a generalized theory of thermal noise, which is sometimes referred to as the fluctuation-dissipation theorem. It is now evident that the mechanical equivalent of the Johnson noise equation provides a useful starting point from which many other device-specific MDF equations may be derived with relative ease. This approach is not restricted to piezoelectric transducers and can be applied regardless of whether the device is intended for operation in a solid, liquid or gaseous medium

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Absolute sensitivity limits of various ultrasonic transducers

Cited by 8 publications

References 9 publications

Determination of the nonlinear ultrasonic parameter using a Michelson interferometer

Determination of the nonlinear ultrasonic parameter using a Michelson interferometer

Effects of Broadband Laser Generated Ultrasound on Array Gain

The minimum signal force detectable in air with a piezoelectric plate transducer

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