Ultrasonic detectors for high-intensity acoustic fields

Abstract The design, construction and performance of two types of miniature ceramic hydrophones are described. They are intended to measure acoustic pressure in a strongly cavitating environment at low ultrasonic frequencies. One of the devices has a diameter of 4 mm; it has a good response curve and a sensitivity of approximately −229 dB with reference to 1 V μPa−1. The other probe is designed to work in a high-temperature cavitating environment; it has 3 mm diameter and a sensitivity of −232 dB with reference to 1 V μPa−1. A specially designed electronic amplifier improves the signal-noise ratio, furnishing a voltage gain of 20 dB in all the band. The impedance adaptation of the signal amplifier allows long wires to be used to conduct the signal to the measuring apparatus.