What does "A-scan" represent in the context of PAUT?

In the context of Phased Array Ultrasonic Testing (PAUT), "A-scan" specifically refers to a display format that represents the amplitude of received ultrasonic signals as a function of time or distance. The A-scan presents information in a one-dimensional format, where the vertical axis indicates the amplitude of the reflected signals, and the horizontal axis represents time or distance, allowing for the identification of reflectors based on their return signals.

This format is particularly useful for determining the presence and location of flaws within a material. By examining the A-scan, an operator can evaluate the strength of the reflection and the time it takes for the sound pulse to return, which is directly related to the distance from the probe to the reflector.

The other choices do not accurately describe the A-scan. A cross-sectional view of a test sample is more representative of B-scan or C-scan displays. A visual representation of reflectors and their positions complements information from an A-scan but is not what the A-scan itself specifically provides. Lastly, while wave velocities can be analyzed through other methods or data interpretations, the A-scan does not serve as a graphical representation of them.