Acoustic Pressure‐Release Techniques for Transducers

Acoustic Transducers and Lens Design for Acoustic Microscopy

The transducer-lens system is one major component in the performance of an acoustic microscope. The design criteria for the various types of applications of an acoustic microscope are different. For surface imaging applications, it is desired to have a small spot size and low sidelobe level. For materials characterization and subsurface imaging applications (sue~ as subsurface crack imaging), i...

Piezoelectric Materials Used in Underwater Acoustic Transducers

Resonant capacitive MEMS acoustic emission transducers

We describe resonant capacitive MEMS transducers developed for use as acoustic emission detectors, fabricated in the commercial three-layer polysilicon surface micromachining process (MUMPs). The 1-cm square device contains six independent transducers in the frequency range between 100 kHz and 500 kHz, and a seventh transducer at 1 MHz. Each transducer is a parallel plate capacitor with one pla...

Scanning acoustic-photoacoustic microscopy using axicon transducers

A dual mode scanning acoustic microscope is investigated, yielding simultaneously images with optical and acoustical contrast. Short laser pulses are used to excite acoustic waves in a sample for the photoacoustic imaging mode. At the same time the pulses irradiate a conical target generating limited diffraction acoustic waves (X-waves) for large depth of field ultrasound imaging. For photoacou...

Electromagnetic Acoustic Transducers for Robotic Nondestructive Inspection in Harsh Environments

Elevated temperature, gamma radiation, and geometric constraints inside dry storage casks for spent nuclear fuel represent a harsh environment for nondestructive inspection of the cask and require that the inspection be conducted with a robotic system. Electromagnetic acoustic transducers (EMATs) using non-contact ultrasonic transduction based on the Lorentz force to excite/receive ultrasonic w...