A METHOD FOR CALIBRATING THE LINE-FOCUS-BEAM ACOUSTIC MICROSCOPY SYSTEM

Absolute accuracy of the line-focus-beam (LFB) acoustic microscopy sys tem is investigated for measurements of the leaky surface acoustic wav e (LSAW) velocity and attenuation, and a method of system calibration is proposed. In order to discuss the accuracy, it is necessary to intr oduce a standard specimen whose bulk acoustic properties, (e.g., the i ndependent elastic constants and density) are measured with high accur acy. Single crystal substrates of gadolinium gallium garnet (GGG) are taken as standard specimens. The LSAW propagation characteristics are measured and compared with the calculated results using the measured b ulk acoustic properties. Calibration is demonstrated for the system us ing two LFB acoustic lens devices with a cylindrical concave surface o f 1-mm radius in the frequency range 100 to 300 MHz.