Summary of a European comparison of ultrasonic power measurements

A summary is given of the results of a European comparison of ultrasonic po wer measurements. Three national metrology institutes participated. All mea surements were carried out using the radiation force balance method accordi ng to International Electrotechnical Commission Standard IEC 61161, with mi nor differences in certain experimental details. Five standard transducers were circulated, with nominal resonance frequencies between 1 MHz and 10 MH z. The measurements covered the power range from IO mW to 200 mW, which rou ghly corresponds to the output of medical diagnostic equipment. The results obtained by the participants agreed within the estimated uncertainties.