The setup developed for experimental validation is shown
in Fig. 1. It consists of a cylindrical tank filled with water for
optimal acoustic coupling between the acoustic detector and
the submerged imaging target. To generate high energy
pulses in the nanosecond range, we utilized a custom-made
pulser consisting of a high-voltage triggered spark gap
Model GP-41B, Perkin Elmer Inc., Waltham, MA for fast
discharge of energies stored in a high-voltage capacitor,
which was charged up to 40 kV. In this way, ultrawideband
high power electromagnetic impulses with durations of
10 ns, carrying energy of up to 0.7 J, were generated see
Sec. III for exact impulse shapes with tunable impulse repetition
frequency in the range of 1–100 Hz. For comparison,
due to substantial costs associated with ultrahigh-peak-power
microwave amplification equipment, the existing pulsed thermoacoustic
sources commonly use much lower energies of a
few millijoules per pulse along with relatively long pulse
durations in the microsecond range.3,17 As a result, the spatial
resolution significantly deteriorates while acquisition times
are prolonged due to extensive signal averaging essential for
noise suppression.

上图是装置