Showing papers on "Time-of-flight diffraction ultrasonics published in 1971"

Ultrasonic Holography in Nondestructive Testing

Abstract: Ultrasonic holography is being evaluated principally on behalf of the Nondestructive Testing Centre at Harwell to determine its usefulness in the field of nondestructive testing. For this purpose a mechanical scanning system has been developed, the salient features of which are that it uses either a single transducer or separate transducers for send and receive, focussed transducers so that resolution depends upon the focal spot size, ultrasonic frequencies up to 10 MHz, an electronic skew plane reference beam whose skewness can be varied, and a facsimile recorder for recording the hologram. The quality of system performance is demonstrated and the results of an experiment to synthesise diffuse illumination are shown. Several results obtained from typical items of interest in nondestructive testing are Shown and discussed to illustrate some of the problems which arise in this field.