Frequency response and self-noise of the MET hydrophone

Abstract

An electrochemical hydrophone based on the principles of molecular electronic transfer (MET) has been described. The paper presents theoretical and experimental results for the sensitivity and the level of selfnoise determination for the MET hydrophone (METH) in the frequency range of 0.02-200 Hz, which determines the fields of acceptance of the devices being developed. An experimental model has been developed by using a force-balancing feedback. Different methods and techniques for its calibration have been developed. The experimental device with 0.75 mV Pa −1 sensitivity flat in the frequency band 0.02-200 Hz has been presented. It has been demonstrated that in the ultra-low-frequency range METH noise could be much lower than the standard Wenz noise model. Easy to produce, cheap and suitable for mass production, the MET hydrophone could be in demand in marine and land acoustic research.Published by Copernicus Publications on behalf of the AMA Association for Sensor Technology.

Frequency Response Stabilization and Comparative Studies of MET Hydrophone at Marine Seismic Exploration Systems

“…Figure 5 shows the measurement results. Compared with the experimental results in [17,22], it can be seen that the measured self-noise in the presented frequency range was not inferior to that measured for a hydrophone with an air bubble. Similar tests with a hydrophone with a partially filled volume of liquid showed that the frequency response curve was more unstable with increasing pressure differences across the membranes.…”

“…The detailed scheme and principle of operation of the MET transducer element and hydrophone (METH) were described in the papers [3,17].…”

“…The principle of operation is that the external pressure acts on the external membrane and drives the liquid in the transducing element due to the compressibility of the liquid filling the internal volume of the hydrophone housing. The volumetric flow q of the working fluid through the sensing element can be represented as follows [17]:…”

“…As a result of comparing the spectra of the hydrophone signals, the frequency response characteristic of the MET hydrophone was obtained. More details about obtaining the frequency response characteristic are described in [17]. Calibration results are shown in Figure 4.…”

“…In previous works [15,16], a model of a MET hydrophone was presented. An experimental sample of the hydrophone was also made and laboratory studies of its main characteristics such as amplitude-frequency response and self-noise were carried out [17,18].…”