Development of a PVDF low-cost shock-wave hydrophone

Abstract

Abstract. During a few past years a series of shock-wave generators for lithotripsy and/or tissue destruction studies have been developed in our laboratory. Based on the experiences in shock wave measurements and the drawbacks in existing hydrophones, we have developed a very low-cost, wideband, reproducible shock-wave hydrophone. The key element of this device is the rapidly mounting, disposable PVDF membrane. This is a commercially available PVDF shock gauge which is poled by a patented cyclic poling technique. To obtain the widest possible bandwidth, we have adopted a special coplanar membrane design. The PVDF film is sandwiched between the surfaces of a P.V.C. and a metallic plate of brass which the latter is in contact with the surrounding medium. On the other hand, the active lead is isolated from medium and it is in contact with an isolating liquid (degassed petroleum) held in a cylindrical chamber over the membrane. By the incorporation of this design, the hydrophone can be used for shock wave measurements even in conductive media like different physiological liquids, with a negligible change of sensitivity.

Modeling of pulsed finite-amplitude focused sound beams in time domain

“…For pressure measurements at the focus, a homemade PVDF shock-wave hydrophone was used. 36 Comparison between the calculated and measured waveforms shows a very good agreement in the shape of waveforms. However, there exists some discrepancy between the pressure amplitudes.…”

“…The discrepancy in the amplitudes may be explained by existing sources of error in our measurements from one hand and in the theoretical model on the other hand. The main sources of uncertainty in our measurements are: pressure-averaging effect over the surface of the hydrophone active element, error in the measured value of the shockwave hydrophone sensitivity, 36 and error in the measurement of the generator electro-acoustical conversion factor at its source surface. 30,37 Among these, we believe that the first one, i.e., the effect of pressure averaging over the surface of hydrophone active element, has had the most important influence on our measurements, especially in nonlinear regime when the focus dimensions become comparable with, or even smaller than, the hydrophone active element size (⌽ϭ1 mm in our measurements͒.…”

Neurostimulation success rate of repetitive‐pulse focused ultrasound in an in vivo giant axon model: An acoustic parametric study

“…Two animals were included in this specific study ( n = 2). The acoustic signatures associated with individual pulses were recorded at a sampling frequency of 62.5 MHz using a low‐cost, wideband hydrophone home‐made with a polyvinylidene fluoride film (25‐μm thickness, 10 mm in diameter) embedded in resin (AY103 Araldite+ 10% HY956) 46,51 . The signal detected by the hydrophone was digitized and recorded using a digital oscilloscope (Picoscope 3000 Series, Pico Technology Ltd.).…”

“…The acoustic signatures associated with individual pulses were recorded at a sampling frequency of 62.5 MHz using a low-cost, wideband hydrophone home-made with a polyvinylidene fluoride film (25μm thickness, 10 mm in diameter) embedded in resin (AY103 Araldite+ 10% HY956). 46,51 The signal detected by the hydrophone was digitized and recorded using a digital oscilloscope (Picoscope 3000 Series, Pico Technology Ltd.). The active area of the hydrophone was placed 5 cm away from the focal area and was oriented toward the focus of the transducer (see Figure 3).…”

Simulation and Experiment of PVDF Temperature Sensor

“…The polarized polyvinylidene fluoride (PVDF) films exhibit good properties in the process of converting the mechanical or caloric energies to the electric signals [1][2][3] . Broad exploitations of these PVDF based sensors have been carried out in the field of robotic haptic communications [4] , sound and ultrasonic applications [5][6][7] , shock sensors [8,9] , and the biomedical utilities [10][11][12][13] . For the overall studies the choice of the readout circuit and technology was crucial to ensure good performance [14] .…”