Ultrasound pulse-echo measurements on rough surfaces with linear array transducers

Abstract

Optimal filter bandwidth for pulse oximetry Rev. Sci. Instrum. 83, 104708 (2012) Optical transduction of E. Coli O157:H7 concentration by using the enhanced Goos-Hänchen shift J. Appl. Phys. 112, 083104 (2012) Detection of virus-like nanoparticles via scattering using a chip-scale optical biosensor Appl. Phys. Lett. 101, 161111 (2012) Role of electropores on membrane blebbing-A model energy-based analysis J. Appl. Phys. 112, 064703 (2012) Additional information on AIP Conf. Proc. Abstract. The echo from planar surfaces with rms roughness, R q , in the range from 0-155 µm was measured with a clinical linear array transducer at different angles of incidence at 6 MHz and 12 MHz. The echo-pulse from the surfaces was isolated with an equal sized window and the power of the echo-pulse was calculated. The power of the echo from the smooth surface (R q = 0) is highly angle-dependent due to a high degree of specular reflection. Within the angular range considered here, -10 • to 10 • , the variation spans a range of 18 dB at both 6 MHz and 12 MHz. When roughness increases, the angle-dependence decreases, as the echo process gradually changes from pure reflection to being predominantly governed by backscattering. The power of the echoes from the two roughest surfaces (R q = 115 µm and 155 µm) are largely independent of angle at both 6 MHz and 12 MHz with a variation of 2 dB in the angular range from -10 • to 10 • . The least rough surfaces (R q = 32 µm and 89 µm) have responses in between with a higher degree of angle-dependence at 6 MHz than at 12 MHz.