A phased array system uses electronic scanning along the length of a linear array probe to create a cross-sectional profile without moving the transducer. As each focal law is sequenced, the associated A-scan is digitized and plotted. Successive apertures are "stacked" creating a live cross sectional view. An animated representation of this sequence a 16 element linear probe with is shown below.
In practice this electronic sweeping is done in real time so a live cross section can be continually viewed as the transducer is physically moved. Below is a real time image with a 64 element Linear phased array probe. In the example below the user programmed the focal law to use 16 elements to form an aperture and sequenced the starting element increments by one. This results in 49 individual waveforms that are stacked to create the real time cross-sectional view across the transducer's
1.5"length.
It is also possible to scan at a fixed angle across elements. As discussed later this is very useful for automated weld inspection. Using a 64 element linear phased array probe with wedge, shear waves can be generated at a user defined angle (often 45, 60 or 70 degrees). With aperture sequencing through the length of the probe full volumetric weld data can be collected without the need for physically increasing distance to weld center line while scanning. This provides for single pass
inspection along the weld length.
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Phased Array Angular Sectorial Scan >>