Ultrasonic intrinsic attenuation measurement using laser techniques

A novel methodology for measuring intrinsic ultrasonic attenuation of compressional waves in polymers (PVC, PE, PC, PMMA) using a noncontacting point laser source and detector is described. The intrinsic character of the attenuation measurements is demonstrated by the independence of the results with respect to the sample size, whereas measurements obtained on the same samples with standard contacting piezoelectric transducers are influenced by diffraction effects which cannot be completely removed by published diffraction corrections. Thus, the ultrasonic-laser method is much more efficient than the piezoelectric-transducer technique for the measurement of intrinsic ultrasonic attenuation