An instrument for ultrasonic measurements of small specimens

An instrument which can be used to measure both sound velocity and attenuation in small specimens (about 5 x 5 x 5 mm(3)) is described, A dual path comparison method based an the ultrasonic pulse transmission method was used in the present work. For this measurement method, an easy-to-handle mercury delay line cell was devised, To test applicability of the instrument, sound velocities were measured at 10 MHz for synthetic silica glasses and a single crystal of sodium chloride along the [100] axis at room temperature, The accuracy of the measurements was better than 0.2%. As a further example, sound velocities and attenuation in the ceramic barium titanate, BaTiO3 were measured in the temperature range from room temperature to 200 degrees C. A large peak was detected in the attenuation near the Curie temperature.