P3K-1 Low Sound Speed and Acoustic Attenuation Silicone Rubber Lens Based on Heavy Density Ceramic Nanopowder Composite for Medical Array Probe

Effects of Yb₂O₃ fine dopant (16 nm) on the acoustic properties of a high-temperature-vulcanization (HTV) silicone rubber have been investigated, in order to develop a new acoustic lens material with a low acoustic attenuation (alpha) for the medical array probe application. The HTV silicone rubber has advantages in that it shows a lower alpha than that of a room-temperature-vulcanization (RTV) silicone rubber and it can be mixed by applying shear stress, using roll-milling equipment. Roll-milling time dependence of the HTV silicone rubber indicates that the alpha is closely affected by the dispersion of nanopowders in the rubber matrix. The 8 vol% Yb₂O₃ doped HTV silicone rubber mixed for 30 minutes showed the lowest a of 0.73 dB/mm/MHz with an acoustic impedance (AI= sound speed (c) x density (rho)) of 1.43 times 10⁶ kg/m²s at 37degC. Moreover, simulation results reveal that a 5 MHz linear probe using the HTV silicone rubber doped with Yb₂O₃ powder showed relative sensitivity around 2.6 dB higher than that in the case of using the RTV silicone rubber doped with Yb₂O₃ powder.