利用激光光声技术测量多层介质的埋层性质

Photoacoustic measurement of thermal properties and thickness of buried layers at multilayer film

摘要: 本文提出了一种表面层为强吸收层的多层介质的光声理论模型,测量了多层金属样品埋层的热扩散率,热传导率及厚度,实验结果与理论很好地符合.表明光声检测在亚表面物性测量方面是一种十分有效的手段。

Abstract: The photoacoustic model of multilayer with a strong-absorbing surface layer is developed. The phase of photoacoustic signal has been measured as a function of modulated frequency using apparatuses that are all controlled by a computer system. The thermal diffusivity, effusivity as well as thickness of several buried layers are obtained independently through best fit of experimental data according to the theoretical model. The multilayers of thin metal and alloy film are investigated and the results show agreement with literature values. This method is proved to be particularly valuable in nondestructive examinations of subsurface physical properties.