Figure 3

Evolution of the ionoacoustic signals with the pulsing period of the mono-energetic proton beam. Measured signals for a 25-cycle proton pulse of 400 ns period in water (gray) compared to (a) simulated signal in water (black dashed line), with (b) SonoVue microbubbles (blue), (c) SonoVue microbubbles / India ink mixture (orange), (d) India ink alone (red). All the experimental measurements have been averaged over 3000 acquisitions. (e) Evolution of the signal amplitude with the pulse period. The amplitude was extracted from the Fourier transform signals at the temporal excitation frequency to disentangle the high and low frequency components of the signal. (f) Phase shift as a function of the pulsing period between the signals measured in water and with CA. All the experimental measurements have been averaged over 3000 acquisitions and filtered using PyWavelets Python package. All error bars correspond to measurement uncertainties obtained from 30 consecutive measurements and given with a confidence level of 99%.