Interlaboratory comparison of hydrophone calibrations

Area of Science:

• Acoustics
• Metrology
• Underwater acoustics

Background:

• Hydrophone calibration is crucial for accurate underwater acoustic measurements.
• Standardization of calibration techniques ensures reliable data across different laboratories.
• High-frequency hydrophone calibration (1-10 MHz) presents unique metrological challenges.

Purpose of the Study:

• To conduct an interlaboratory comparison of hydrophone calibration techniques.
• To assess the agreement between different calibration methods in the 1-10 MHz frequency range.
• To evaluate the consistency of hydrophone sensitivity measurements.

Main Methods:

• Six laboratories participated in the comparison.
• Two membrane hydrophones were calibrated using standard laboratory procedures.
• Calibration methods included optical interferometry, planar scanning, reciprocity with time-delay spectrometry, and suspended-sphere radiometry.

Main Results:

• End-of-cable loaded sensitivities were determined by each laboratory.
• Results were converted to end-of-cable open-circuit sensitivities for comparison.
• Agreement between the various calibration methods was within +/-10% across the 1-10 MHz frequency range.

Conclusions:

• The interlaboratory comparison demonstrated good agreement among diverse hydrophone calibration techniques.
• The findings support the reliability of current methods for high-frequency hydrophone calibration.
• This study contributes to the standardization and validation of hydrophone sensitivity measurements.