7. Non Metallic NDE, Acoustic Microscopy
The Reflection Acoustic Microscope, operating at a microwave frequency near 400 MHz, has been used to image and examine subsurface detail in a multilayer ceramic chip capacitor (MCCC). Bulk examination of the 0.9 mm thick MCCC is at present not possible with this high resolution acoustic microscope because of the short depth of focus of the particular lens designed for the system and because of the short wavelength ( w 4 m).
Weglein, R. D. and Bergren, D. A., "Nondestructive Subsurface Imaging with the Reflection Acoustic Microscope" (1980). Proceedings of the DARPA/AFML Review of Progress in Quantitative NDE, July 1978–September 1979. 46.