Which type of phased array scan is equivalent to a conventional ultrasonic probe performing a raster scan?

The correct choice is the E-scan. In the context of phased array ultrasonic testing, an E-scan refers to a scanning technique that resembles the raster scan performed by a conventional ultrasonic probe.

In a raster scan, the probe moves linearly and covers a designated area systematically, much like a television screen refreshes. The E-scan similarly captures data across a predefined grid by electronically steering the probe's beam in both horizontal and vertical axes. This results in a comprehensive view of the test area and allows for the accumulation of data in a way that presents a continuous image of the scanned object.

The choice of E-scan is appropriate because it highlights how the movement and scanning technique align with conventional scanning methods, facilitating an effective comparison and understanding of the phased array functionality relative to traditional ultrasonic testing.

Other types of scans, like the azimuthal scan, S-scan, or compound sector scan, do not replicate the raster scanning behavior and serve different purposes. The azimuthal scan typically focuses on mapping data in a circular pattern, while the S-scan specifically refers to the display of multiple parallel waveforms that provide insights into reflectors or discontinuities. The compound sector scan offers a broader sectoral coverage but does not mimic the linear raster