Abstract :
Bausch and Lomb T-40 glass is used in ultrasonic delay lines because it combines a low temperature coefficient of delay for shear waves with a low acoustic loss. Although the acoustic loss in the glass is higher than that of vitreous silica, it is low enough to permit the design of lines having sufficient storage capacity to be useful in applications such as storage devices for digital data or delay devices for color television receivers. The low temperature coefficient makes this material attractive for use in locations which may undergo ambient changes of 50 to 60°C. The attenuation coefficient u of the material has been measured in the frequency range of 1.0 to 300 MHz, and when the data are plotted with log α versus logj, a straight line is obtained with a slope equal to 1.30. The attenuation coefficient α is slightly dependent upon temperature, decreasing 0.3% °C with increasing temperature.
