Beam Exit Point

Beam Exit Point

In PAUT, each beam has its own exit point on the wedge. There is no single exit point like in conventional UT. 

1. A beam at 35° is produced by the wave front. It has a specific exit point on the wedge
2. A beam at 55° is produced by the wave front. It has another specific exit point on the wedge
3. Finally a beam at 70° is produced by the wave front. It has another specific exit point on the wedge
4. All the beams in-between have their own exit point

Since the exit point varies for each beam, it is very difficult to give the surface distance from the exit point. This is the reason why the surface distance in PAUT is always given from the front (or back) of the wedge.