The best probe for phased array inspection of thick welds will depend on a number of factors, including the thickness of the weld, the material being welded, and the specific requirements of the inspection. In general, however, it is important to choose a probe with a high frequency and a small footprint, as this will provide the best resolution and penetration for thick welds. Some common probes that are often used for phased array inspection of thick welds include:

• 2D linear array probes: These probes are designed for inspecting large areas and have a rectangular or square shape. They are often used for weld inspection, as they provide good resolution and penetration, and can be used with a variety of different scanners and wedges.

• 2D phased array probes: These probes are similar to linear array probes, but they use multiple elements to produce a phased array beam, which provides improved resolution and penetration. They are often used for inspecting thick welds, as they can provide a clear, detailed image of the weld even at high thicknesses.

• Sector array probes: These probes are shaped like a sector of a circle and are used for inspecting curved or angled surfaces. They are often used for weld inspection, as they provide good resolution and penetration and can be used with a variety of different scanners and wedges.

• Focused probes: These probes are designed to produce a focused, highly directional beam that provides improved resolution and penetration. They are often used for inspecting thick welds, as they can provide a clear, detailed image of the weld even at high thicknesses.