In addition to other functions, a probe manipulator in a mechanical immersion scanning unit permits which of the following?

A probe manipulator in a mechanical immersion scanning unit is designed to enhance the capabilities of ultrasonic testing by allowing for precise adjustments in the positioning of the probe. This is particularly significant when it comes to detecting obliquely-oriented discontinuities.

The ability to angle the probe accurately increases the likelihood of capturing reflections from flaws that may not be aligned directly with the ultrasound beam. Such adjustments help in achieving optimal coupling between the probe and the test material, thereby improving detection sensitivity. This is especially important in complex geometries or materials where discontinuities may not be parallel to the scanning surface.

While the other functions described in the options relate to ultrasonic testing and probe functionality, they do not specifically highlight the unique advantage that a probe manipulator offers in addressing the challenges posed by angled discontinuities, which can often be missed if the probe is held statically or at a fixed angle. Thus, the ability to change angles and effectively detect flaws that are not aligned directly with the scanning direction is one of the primary benefits of using a probe manipulator in immersion scanning setups.