High-sensitivity hydrophones

A hydrophone that has been designed for high-sensitivity gains is one which has been configured for acoustic detection along the g,i axis (as opposed to the common gn or... 

In these studies, we used unfocused ultrasound with a frequency of 0.88 MHz and an intensity of 2 W/cm. Cavitation properties of gels containing impurities and without them were comparatively estimated using an IS-3 MS cavitation indicator developed at the Belarusian State University of Informatics and Radioelectronics. The device s operating principle is based on the measurement of the level of scattered noise in a frequency band from 2 to 10 MHz, received by a broadband hydrophone. An emitter 2 cm in diameter was in direct contact with the face of the cylindrical gel sample (2 cm high and 2.5 cm in diameter), that is, measurements were performed in the transducer s near field. The hydrophone with a sensitive element 2 mm in diameter was placed in the immediate vicinity from the side surface of the sample. 

The hydrophone figure of merit is the product When the piezoelectric has a high K, inexpensive preamplifiers can be used. The open-circuit hydrophone sensitivity is expressed as output voltage per input plane wave pressure ... 

For piezoelectric homopolyiner there is a difiference in the (3,1) and (33) modes because of the stretdiing and poling processes involved during the fabrication. This means that fenocleclric homopolymers have a relatively high and usefol hydrostatic re-ceivittg sensitivity. Because of tl ferroelectric homopolyiner hydrophones have found favor in hydrostatic-mode applicatioos. 

The results discussed in this chapter can promote the selection of the proper SC and FC components for novel composites with high piezoelectric sensitivity, large piezoelectric anisotropy, considerable hydrostatic response, and other remarkable effective parameters. It is believed that the development of high-performance composites will be attraetive for modem piezotechnical applications (sensors, hydrophones, transdueers, etc.). 

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