Pulse-echo field distribution measurement technique for high-frequency ultrasound sources

A simple technique for the determination of the spatial and temporal transmit-receive field distributions of spherically focused high-frequency transducers is described. Instead of a point-like target, tungsten wires (line-like targets) with diameters less than the acoustic wavelength are used as pulse-echo targets. Spatial and temporal field quantities were determined for spherically focused transducers in the frequency range from 3 to 17 MHz, and a comparison with hydrophone measurements showed that both techniques yielded comparable results for the low-frequency transducer. However, for the higher frequency transducers, hydrophone measurements did not yield satisfactory results compared to the wire-target technique due to the hydrophone's aperture size, while the results from the wire-target technique were in general agreement with theory.