10.202015NDT.net technical tip: to focus or not to focusCategory "NDT Consulting and Techniques" | No comment

Ed Ginzel, retired consultant with Materials Research Institute, active member of the NDT.net community and CIVA user, explains in a technical tip why a focused beam should not be used for general weld inspection.
His demonstration based on CIVA simulation can be downloaded here. It shows that the increase of sensitivity due to focusing is done at the expense of reducing sensitivity in the weld/HAZ zone, thereby requiring the operator to use more receiver gain in the TCG construction in the region of interest. As a result of the increased beam spread that occurs after the focal point, there is reduced beam resolution. Therefore, closely spaced indications are more difficult to resolve.
This tip is open to discussion in the NDT.net forum. Don’t hesitate participating!
The EXTENDE's team