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

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 (alpha). Silicone rubber doped with Yb2O3 powders having nanopowder size of 16 nm showed lower alpha than silicone rubber doped with other powders. The silicone rubber doped with Yb2O3 powder showed a density of 1.54 times 103 kg/m3, c=919 m/s, an acoustic impedance Z= 1.42 times 106 kg/m2s, alpha = 1.08 dB/mm/MHz at 25degC. The low c and alpha of the lens material contributes to realize a low loss acoustic lens for medical array probes for diagnostic application.