Semiconductor pressure-pulse sensor

The use of a semiconductor pressure sensor based on AlGaAs thin films to measure shock-wave pressures in lithotripters is described. The selection of an optimal thickness of encapsulant on the face of the pressure-sensitive chip enables a satisfactory durability and dynamic accuracy of the sensors to be obtained. Pressure sensors with a diameter of 1.3 mm have a sensitivity of 1.5 mV MPa(-1), a durability of about 2 x 10(4) pressure pulses of 40 MPa in amplitude and a rise time less than 0.1 mu s. The advantages and disadvantages of the proposed sensor as compared to pressure-pulse sensors of other types are discussed.