Related Experiment Videos
1-60 MHz measurements in focused acoustic fields using spatial averaging corrections
E G Radulescu1, P A Lewin, A Nowicki
1School of Biomedical Engineering, Science and Health Systems, Department of Electrical and Computer Engineering, Drexel University, Philadelphia, PA 19104, USA.
Ultrasonics
|August 6, 2002
Summary
A new measurement technique rapidly characterizes ultrasound hydrophone probes above 20 MHz. This method uses focused acoustics and spatial averaging correction, achieving +/- 1 dB uncertainty for reliable, high-frequency ultrasound characterization.
Area of Science:
- Acoustics
- Metrology
- Materials Science
Background:
- Accurate characterization of ultrasound hydrophone probes is crucial for diagnostic and therapeutic ultrasound applications.
- Existing methods often face limitations in speed and accuracy at higher frequencies (above 20 MHz).
- Polyvinylidene fluoride (PVDF) hydrophones are widely used due to their piezoelectric properties.
Purpose of the Study:
- To develop and verify a rapid and dependable measurement technique for characterizing ultrasound hydrophone probes.
- To extend reliable characterization capabilities to frequencies beyond 20 MHz, up to 60 MHz and beyond.
- To quantify the uncertainty and identify limitations of the developed technique.
Main Methods:
- Employed focused acoustic sources to enhance signal-to-noise ratio.
- Utilized a spatial averaging correction model to compensate for the finite aperture of hydrophone probes.
- Applied a substitution technique for efficient calibration, tested up to 60 MHz.
Main Results:
- Achieved an overall measurement uncertainty of approximately +/- 1 dB.
- Successfully characterized both needle and membrane type PVDF hydrophones with effective diameters from 130-1200 microns.
- Determined that spatial averaging error depends on beam cross-section and hydrophone diameter ratios.
Conclusions:
- The developed measurement technique provides rapid and dependable characterization of ultrasound hydrophone probes at high frequencies.
- The technique is applicable to various hydrophone types and sizes, with proven performance up to 60 MHz.
- Ongoing work aims to extend the technique's capabilities to frequencies exceeding 60 MHz.