Velocity of Ultrasound Wave in Helium, Argon, and Nitrogen Gases at High Pressure

Velocities of ultrasound waves in helium, argon, and nitrogen gases have been measured at 25°C under high pressure up to 15 KB for helium and nitrogen, and 13 KB for argon where it solidifies, using a single-pulse ultrasonic technique. Lead zirconate titanate ceramics with fundamental frequencies of 1 and 2 MHz are used as transducers. The observed velocities of ultrasound waves are in good agreement with the previous data. The ratios of specific heats are also calculated.