A membrane sampler for lithotripter monitoring

A simple membrane deflector is described that enables continuous monitoring of lithotripter shock-wave pulses to be achieved using standard hydrophones. The device discussed here comprises a thin planar plastic membrane supported by a rigid frame. The area of the membrane is chosen to intersect the whole cross section of the converging beam well in front of the focus. A thin membrane deflector is shown to allow the use of miniature hydrophones without risk of damage. Theoretical and experimental results are presented for several materials, and the conditions for accurate sampling of highly convergent wideband acoustic pulses are shown to be related to the behavior of leaky Lamb waves in immersed plates