How is the term “sector scan” defined in phased array ultrasonic testing?

In phased array ultrasonic testing, the term “sector scan” refers to a technique where the sound beam is electronically swept through a specified angle. This method effectively allows the inspector to cover a portion of the material being tested, creating a sector or wedge shape where the ultrasound beam is directed. The ability to program the beam's angle and focus dynamically makes this technique highly efficient for identifying defects in various locations without the need to move the probe extensively.

In contrast, methods that examine only surface defects or are applicable exclusively to thick materials would not utilize the features or capabilities inherent in sector scanning. Additionally, while a scanning method could create various patterns, the circular pattern is more indicative of a different scanning type, rather than the segmented approach used in sector scans. Thus, the defining characteristic of a sector scan being focused on the beam’s angular sweep is what differentiates it as an integral method in phased array ultrasonic testing.