ASA 126th Meeting Denver 1993 October 4-8

4aEA1. Standard reversible transducer (USRD type E37) for high frequencies to 2.0 MHz at hydrostatic pressures to 20.7 kPa (3000 psi).

James A. Tims Larry E. Ivey

Naval Res. Lab., Underwater Sound Reference Detachment, P.O. Box 568337, Orlando, FL 32856-8337

A new pressure-stable reversible standard transducer, USRD E37, has been developed at the Naval Research Laboratory, Underwater Sound Reference Detachment for the frequency range 100 kHz to 2.0 MHz at hydrostatic pressure to 20.7 MPa (3000 psi) with operating temperatures from 5 to 35 (degrees)C within this frequency range. This USRD E37 maintains a smooth response over the broad frequency spectrum previously covered by both the USRD E27 and E8 standard transducers, which were not stable with temperature and static pressure. The E37 has been calibrated to 6894 kPa (1000 psi) at 3 (degrees)C. Its unique sensor configuration design uses a lead titanate disc sensor supported by a butyl rubber ring. The faces of the sensor are covered with PRC PR-1538 polyurethane and are held in place in the frame assembly by thin wire. The receiver preamplifier assembly is specially designed for high-frequency operation, with a built-in bypass relay to allow signals to be transmitted. The cylindrically designed outer housing is made of polycarbonate and has been statically pressure tested to 31.026 MPa (4500 psi).