Malcher, F; Ford, B; Barham, R; Robinson, S; Ward, J; Wang, L; Bridges, A; Yacoot, A; Cheong, S H; Rodrigues, D; Barrera-Figueroa, S (2024) A calculable pistonphone for the absolute calibration of hydrophones in the frequency range from 0.5 Hz to 250 Hz. Metrologia, 61 (2). 025011

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Abstract

The demand for traceable hydrophone calibrations at low frequencies in support of ocean monitoring applications requires primary standard methods that are able to realise the acoustic pascal. In this paper, a new method for primary calibration of hydrophones is described based on the use of a calculable pistonphone to cover frequencies from 0.5 Hz to 250 Hz. The design consists of a pre-stressed piezoelectric stack driving a piston to create a varying pressure in an air-filled enclosed cavity, the displacement (and so the volume velocity) of the piston being measured by a laser interferometer. The dimensions of the front cavity were designed to allow the calibration of reference hydrophones, but it may also be used to calibrate microphones. Examples of calibration results for several sensors are presented with an uncertainty budget. The metrological performance is demonstrated by comparisons with results for other calibration methods and an independent implementation of primary calibration methods at other institutes.

Item Type:	Article
Keywords:	infrasound, calibration, calculable pistonphone, hydrophone, underwater acoustics
Subjects:	Acoustics > Underwater Acoustics
Divisions:	Medical, Marine & Nuclear
Identification number/DOI:	10.1088/1681-7575/ad2d5a
Last Modified:	10 Sep 2024 14:48
URI:	https://eprintspublications.npl.co.uk/id/eprint/10011