What does an "A-scan" represent in phased array testing?

In phased array testing, an "A-scan" represents a one-dimensional representation of ultrasound signals. This type of scan provides a single trace showing the amplitude of the received ultrasonic signals plotted against time or distance. In practical terms, an A-scan helps visualize the depth of detected anomalies within a material, as the peaks in the graph indicate the time it takes for echoes to return from interfaces or flaws within the test piece.

The A-scan is critical in analyzing signal characteristics such as signal amplitude and travel time, which are essential for determining the size and location of defects. This one-dimensional format is most beneficial for simple evaluations where precise depth measurements and signal strength assessments are required. It serves as the foundation upon which more complex data representations like B-scans or C-scans can be built, which provide additional dimensions of analysis.