The Naval Research Laboratory has operated one of these sources for over 10 years. The Deep Water Acoustic Source is a Helmholtz Resonator type transducer with output from 250 Hz - 900 Hz at 201 dB re: 1 uPa @ 1 m.

Output can be a swept chirp or a pulsed contant frequency, capable of achieving spatial resolution on the order of 5 meters. This source will operate in water depths up to 6,000 meters or 19,685 feet. The output waveform is calibrated and highly repeatable. The Helmholtz Transducer is made up of a stack of five piezoelectric ceramic rings inside an oil-filled rubber boot. Each ring is pre-stressed so the ceramic remains in compression while operating.

The Deep Water Acoustic Source bridges the gap in scale between convential surface-tow seismic systems and high resolution sidescan systems. This source has applications in high resolution sub-bottom seismic studies such as:

• Geotechnical studies for sea floor structure emplacement
• Gas hydrate distribution and characterization
• Sub-bottom geologic processes

This source can also be used in acoustic applications. For example:

• Acoustic characterization of the sea floor and ocean subbottom
• Acoustic tomography
• Acoustic backscatter studies

The physical dimension of the source are 0.7 meters in diameter by 1.08 meters (3.5 feet) in length, weighing 812 kg (1790 lbs) in air and 612 kg (1349 lbs) in water.