I have seen only two digital oscillograms of the pressure waves from
apparent NAE in the SPAWAR experiments, these were clear
characteristic signals, a sharp spike followed by a relaxation. The
frequency of occurrence of these spikes may be a few per second, and
I'm guessing that they correspond to the heat flashes that the SPAWAR
IR imaging shows.
If I set up not just one piezoelectric transducer, but four or six,
it should be possible to locate the source of each shock. The entire
cell is on the order of 20 microseconds wide at the speed of sound in
water, so normally signals from the sensors that match within that
window would be coming from a common event. It should be possible to
filter the transducer signals and determine the relative arrival time
of each signal, and, from that, with each pair of sensors, determine
a coordinate of the source.
But it may not be necessary. If the sound is characteristic and not
produced when nuclear activity doesn't occur, then one sensor is
enough to do the basic job.
