In order to balance wide bandwidth with durability, a hydrophone for lithotripsy research was developed using disposable elements of 9 micron thick PVDF copolymer film. Each element, which measures 1 cm x 10 cm and is stretched across a plexiglass frame, contains .2 mm-wide electrodes overlapping in a crosshair pattern at the element center. When an element fails, it may be quickly replaced. To avoid the need for recalibration with each replacement, the use of hysteresis poling ensures constant sensitivity of elements [E. Carr Everbach, J. Acoust. Soc. Am. S1 (87), S128]. Electronics located in the frame include a wide-bandwidth preamplifier and gating circuitry to prevent saturation by the electromagnetic pulse from a spark-gap lithotripter. This design provides the needed bandwidth to resolve shock wave frequency components beyond 100 MHz, as well as the durability and spatial resolution necessary to map the acoustic field within a lithotripter. [Work supported by an NSF PFF]

This paper was presented 11/30/95 at the 130th meeting of the ASA, in the special session on Lithotripsy.