Absolute calibration of hydrophones immersed in sandy sediment

Robb, Gary B.N.; Robinson, Stephen P.; Theobald, Pete D.; Hayman, Gary; Humphrey, Victor F.; Leighton, Timothy G.; Wang, Lian Sheng; Dix, Justin K.; Best, Angus I. ORCID: https://orcid.org/0000-0001-9558-4261. 2009 Absolute calibration of hydrophones immersed in sandy sediment. Journal of the Acoustical Society of America, 125 (5). 2918-2927. 10.1121/1.3106530

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Official URL: http://dx.doi.org/10.1121/1.3106530

Abstract/Summary

An absolute calibration method has been developed based on the method of three-transducer spherical-wave reciprocity for the calibration of hydrophones when immersed in sandy sediment. The method enables the determination of the magnitude of the free-field voltage receive sensitivity of the hydrophone. Adoption of a co-linear configuration allows the acoustic attenuation within the sediment to be eliminated from the sensitivity calculation. Example calibrations have been performed on two hydrophones inserted into sandy sediment over the frequency range from 10 to 200 kHz. In general, a reduction in sensitivity was observed, with average reductions over the frequency range tested of 3.2 and 3.6 dB with respect to the equivalent water-based calibrations for the two hydrophones tested. Repeated measurements were undertaken to assess the robustness of the method to both the influence of the sediment disturbance associated with the hydrophone insertion and the presence of the central hydrophone. A simple finite element model, developed for one of the hydrophone designs, shows good qualitative agreement with the observed differences from water-based calibrations. The method described in this paper will be of interest to all those undertaking acoustic measurements with hydrophones immersed in sediment where the absolute sensitivity is important.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1121/1.3106530
ISSN:	0001-4966
Date made live:	11 Jan 2010 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/171904

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1121/1.3106530

ISSN:

0001-4966

Date made live:

11 Jan 2010 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/171904