A Pulsed Hypersonic Technique and Some Attenuation Measurements in Quartz at Low Temperatures

Abstract

Abstract : Conventional pulsed surface excitation of quartz in the kilomegacycle range of frquencies almost invariably produces non-exponentially decaying echo envelopes, making reliable attenuation measurements difficult. This difficulty can frequently be overcome by the use of conventional transducers and by careful bonding techniques. This transducer technique, methods of simultaneously generating compressional and shear modes in quartz and a tunable cavity capable of being operated over a wide frequency range are described. Applications of this equipment to the measurement of attenuation of hypersound in single crystal quartz as a function of transmitter power and of temperature below 20 K are briefly described. (Author)