A Broadband Technique for Couplant-Corrected Pulse-Echo Measurements in a Large Volume Pressure Cell

Ultrasound Pulse-Echo measurements are widely used to determine highly accurate sound speeds and elastic moduli. The most accurate of these measurements accounts for the effect of the acoustic couplant used between a buffer rod and a sample to promote energy transfer through the interface. However, the data acquisition traditionally required for this correction can be time consuming, lasting tens of minutes. This time consumption limits the usability of this approach for measurements on dynamic systems or where time resolved measurements are desired. This work reports on the development and demonstration of a broadband ultrasound pulse-echo technique which enables the frequency dependent couplant correction to be made with data acquisition times that are 20–30 times faster than the traditional approach. The technique is demonstrated on measurements of samples inside a large volume pressure cell. Such measurements enable the determination of the pressure dependence of sound speeds and thus a material's Third Order Elastic Constants, needed for the design of acoustic wave devices intended for high acceleration environments.