Scattering of ultrasound pulses in a suspension of particles

This paper presents an experimental study of the propagation and scattering characteristics of ultrasound pulses in a suspension of particles, and comparisons with recent theoretical study on pulse diffusion [A. Ishimaru, J. Opt. Soc. Am. 68, 1045 (1978)]. Ultrasound offers some advantages over optical experiments because of its low velocity of propagation. Experiments are performed using bursts of 5-MHz pulses of 10-μs duration. The sample chamber is 5 ∼ 10 cm long and contains polystyrene particles of 0.6-μm diameter suspended in a self-buoyant solution of sugar and detergent. The transmitted pulse consists of coherent and incoherent waves. The coherent wave has a pulse shape identical to the incident pulse and it diminishes as the density is increased. The incoherent pulse is spread out in time and increases with the increase of particle density. The experimental data are consistent with the theoretical predictions.