Inexpensive Acoustoelectric Hydrophone For Mapping High Intensity Ultrasonic Fields.

We describe an inexpensive alternative to conventional hydrophones for measuring ultrasonic fields. The hydrophone, composed of common laboratory supplies, depends on the acoustoelectric (AE) effect, a well-known interaction between electrical current and pressure. Beam patterns of a 540 kHz annular transducer captured using a bowtie graphite hydrophone were consistent with patterns obtained using conventional, more expensive hydrophones. The AE signal was proportional to both the applied bias current (1.83 µV/mA) and pressure (13.3 µV/MPa) with sensitivity better than 50 kPa. Disposable AE hydrophones may be an attractive alternative for clinical applications that require close monitoring of high intensity acoustic fields.