Long acoustic imaging probes

Theoretical considerations and experimental measurements on two long acoustic imaging probes are presented. One is a cladded glass rod and the other is a glass rod with a graded acoustic velocity profile across the rod diameter. The acoustic velocity profiles have been measured using a 225-MHz line focus beam scanning acoustic microscope. Spherical acoustic lenses have been fabricated at the ends of the rods. Focused and unfocused ultrasonic measurements obtained with these long buffer rods at ambient and elevated temperatures are demonstrated.<>