In PAUT examination using S-scans, what does the use of side-drilled holes during calibration allow for?

The use of side-drilled holes during calibration of a Phased Array Ultrasonic Testing (PAUT) examination allows for angle corrected gain compensation. This process is essential because it ensures the ultrasonic signals are accurately compensated based on the angle of incidence at which the sound waves interact with the material.

When using phased array technology, it is critical to understand how the ultrasonic waves behave at various angles and how depth and geometry affect the returned signals. Side-drilled holes serve as precise reflectors within the test medium, which help in assessing the angle-dependent response of the ultrasonic waves. By analyzing the reflections from these holes, technicians can calibrate the system to compensate for signal variations that occur due to angle changes during testing.

This calibration process enhances the reliability and accuracy of the inspection by ensuring that the gain is properly adjusted for different scanning angles. Such adjustments allow for a more effective interpretation of defects and discontinuities within the material being inspected. Other options are less relevant to this specific calibration technique, as they pertain to different aspects of ultrasonic testing measurement standards.