AN INSTRUMENT FOR MEASURING ULTRASONIC ATTENUATION, INTERNAL FRICTION AND VELOCITY OF SOUND AT MEGAHERTZ FREQUENCIES

An instrument for measuring ultrasonic attenuation by means of comparing the ultrasonic pulse echo with a calibrated exponential decay wave-form is described. This instrument is designed to make ultrasonic measurement in the frequency range of 5MHz to 55 MHz and in the attenuation coefficient range of 0.01dB/μs to 3dB/μs. It is capable of . making sound velocity measurements in solid with an accuracy of±0.1%. Internal friction in a single crystal of pure aluminium was measured with this equipment.