Low Sound Velocity and Acoustic Attenuation Silicone Rubber Lens Based on Nano-Powder-Composite for Medical Echo Ultrasound Array Probes

Abstract

Effects of fine nano-powder ceramic powders on the acoustic properties of silicone rubber have been investigated, in order to develop an acoustic lens material with a low sound velocity (c) and a low acoustic attenuation (α). Silicone rubber doped with Yb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> powders having nanopowder size of 16 nm showed lower α than silicone rubber doped with other powders. The silicone rubber doped with Yb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> powder showed a density of 1.54 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> kg/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> , c=919 m/s, an acoustic impedance Z= 1.42 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> kg/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> s, α = 1.08 dB/mm/MHz at 25°C. The low c and α of the lens material contributes to realize a low loss acoustic lens for medical array probes for diagnostic application.