Primary measurement of ultrasonic power and dissemination of ultrasonic power reference values by means of standard transducers

Abstract

The time-average ultrasonic power emitted by an ultrasonic transducer is one of the key values characterizing the strength of ultrasonic fields as a whole. For medical applications in particular, measurements are usually carried out in water and in the frequency range 1 MHz to 10 MHz. The use of a radiation force balance is recommended in International Electrotechnical Commission Standard IEC 61161. This measurement method and its practical realization at the Physikalisch-Technische Bundesanstalt are described. Uncertainties involved in the primary measurement and in the dissemination process are discussed.