Final report on key comparison CCAUV.U-K3.1

In October 2013, during 9th meeting CCAUV in Sevres, France, key presented Draft B report agreed upon shortly thereafter by email. results have also been published in meantime [1]. During meeting it was decided to start newcomparison CCAUV.U-K3.1 to give all participants of preceding loop who delivered discrepant valuesthe opportunity to perform new measurements. In addition, NMIJ was included since institute could not take part in CCAUV.U-K3 because horrible earthquake in 2011. Furthermore, NMC A*STAR had for opportunity to take part, but resigned later from comparison. The goal key was to show participating laboratories to determine the acoustic radiation conductance an transducer by measuring total time-averaged ultrasonic power emitted for an applied rms in nominal frequency range from 2 to 16 MHz for nominal output power values between 10 mW and 15 W. Although ultrasound power is measurand key comparison, participants were asked to report radiation conductance whichis independent applied voltage is therefore characteristic property transducer at a particular frequency. Nevertheless, key comparison primarily represents ultrasound power measurement capabilities participating NMIs is suitable for justifying CMC entries this variable. This key was planned conducted according to “Guidelines for CIPM Key Comparisons” issued by BIPM [2].