Location

La Jolla, CA

Start Date

1-1-1983 12:00 AM

Description

We have developed a technique for imaging variation in the surface characteristics of a sample by measuring the local perturbation of the Rayleigh wave velocity. A 50 MHz acoustic microscope operated out-of-focus is excited with a very short tone burst so that the on-axis longitudinal and off-axis Rayleigh reflection pulses are temporally separated. The relative phase between these two signals is measured using a synchronous detection scheme. This technique has a potential sensitivity of 10 ppm. We have demonstrated experimentally that we can detect a 240 Å thick film of indium deposited on glass which corresponds to a velocity perturbation of 0.18%.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

2B

Chapter

Section 23: Acoustic Imaging

Pages

1643-1652

DOI

10.1007/978-1-4613-3706-5_109

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Precision Measurement of Rayleigh Wave Velocity Perturbation

La Jolla, CA

We have developed a technique for imaging variation in the surface characteristics of a sample by measuring the local perturbation of the Rayleigh wave velocity. A 50 MHz acoustic microscope operated out-of-focus is excited with a very short tone burst so that the on-axis longitudinal and off-axis Rayleigh reflection pulses are temporally separated. The relative phase between these two signals is measured using a synchronous detection scheme. This technique has a potential sensitivity of 10 ppm. We have demonstrated experimentally that we can detect a 240 Å thick film of indium deposited on glass which corresponds to a velocity perturbation of 0.18%.