Measurement of Acoustic Nonlinearity Parameter of Small-Volume Liquid Sample Using Focused Ultrasound

概要

論文の詳細を見る
A finite-amplitude measurement method for the acoustic nonlinearity parameter $B/A$ of a liquid sample with a volume as small as 0.1 ml is realized using a focused ultrasound of 18.6 MHz fundamental frequency with the focal length of 10.65 mm. The liquid sample is packed into a 1-mm-thick sample cell set at the focal region where the $1/e$ beam width is 0.2 mm. The sample is separated from the water couplant by an acoustic window of 5-μm-thick poly(ethylene terephtalate) (PET) film. The LiNbO3 transducer with an inverted polarization layer is capable of receiving the 37.2 MHz nonlinearly generated second harmonic sound. The second harmonic component contained in the sound returned from a rigid reflector set at the focal plane just behind the sample is observed and utilized for calculating $B/A$, taking into account the transmission loss due to the acoustic window. The linear acoustic properties of the sample and acoustic window film necessary for calculating $B/A$ are also measured utilizing the benefit of the transducer with inverted polarization layer. The results of measurements of liquids with known $B/A$ values validate the present measurement method.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2008-05-25