Ultrasonic propagation in various gases at elevated pressures

Abstract

Ultrasonic propagation has been studied in air, helium (He) and carbon dioxide (CO2)at pressures of up to 2 bar. The experiments were carried out using an inexpensivepressure chamber, manufactured from commercially available components.Accurate measurements of ultrasonic attenuation were performed, taking intoaccount the diffraction effects of the transducers. It is also shown that ultrasonictransmission through solid materials, such as cardboard, can be enhanced at highpressures, using capacitive transducers whose performance is enhanced under suchconditions.