High-Pressure Piezoelectric Ceramic Hydrophone for Infrasonic and Audio Frequencies USRD Type H48

Abstract : A pressure-sensitive reference hydrophone for the frequency range 0.3 Hz to 20 kHz at hydrostatic pressure to 68.9 megapascals (10,000 psi) and temperature from 0 to 30C has been developed. The nominal open-circuit crystal sensitivity of the hydrophone is -199 plus or minus 1 dB re 1 V/micropascals from 1 Hz to 20 kHz; the output of the lead zirconate-titanate spherical element is increased by a transistorized, 10-dB-gain preamplifier. A novel cable gland improves the high-pressure reliability of the hydrophone.