Pulse-reflection acoustic microscope

A wide-field pulse scanning acoustic microscope (WFPAM) was used in the reflection mode at the driving frequencies of / = 25 — 50 — 100 MHz to measure the local values of ultrasonic velocities and elastic moduli (the microacoustic technique) and to visualize the bulk microstructure of a specimen (scanning acoustic microscopy). The method makes it possible to measure the elastic characteristics of small specimens and inclusions [26,27]. 

We used 900-MHz scanning acoustic microscopy to assess the acoustic impedance with a micrometer resolution. Acoustic microscopy measures the amphtude of a high frequency ultrasonic pulse reflected from the surface of a materM. The microscope is calibrated with a set of materials which have... 

The standard piece of equi( nent used in AMI is the C-Mode Scanning Acoustic Microscope (C-SAM ). The system is a pulse-echo (reflection type) microscope that generates images by mechanically moving a transducer back and forth, in a raster pattern, over the sample. The source transducer is a focused acoustic lens assembly and is coupled to the sample by fluid medium - usually de-ionized water or some type of inert fluid. The transducer has piezoelecoric properties, which allow it to aa as both a sender and receiver being electronically switched back and forth between transmit and receive modes (Figure 2). 

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