Delay law Focalization in Gekko


Delay laws are in essence what phased-array technique is all about. We can electronically scan, steer and focus the energy by adapting the time delay to each element. Let’s focus today (no pun intended) to focalization.

Focalization, as its name implies, focuses the energy to a small spot. This improves the lateral resolution, thus the ability to dissociate two close indications (Why 64 elements). But is also improves the Signal-To-Noise ratio by sending more energy onto the indications (Improved SNR).

It is however important to focus the energy in the right spot. To help operators deal with most situations, Gekko offers three focusing possibilities on the equipment, no need to calculate on an external software and/or to import the delay laws:

  • Depth focusing
  • Constant soundpath focusing
  • Constant distance focusing

 

 

 

Depth focusing is the most known and the one typically used on most phased-array equipment. The operator simply specifies the depth of the focalization points.

We look here at the row of 1-mm side-drilled holes (SDH) aligned at 10 mm in the ASTM 2491 mockup.

 

 

Soundpath focusing: the Gekko focuses the energy at constant soundpath.

The ASTM 2491 mockup has two arrays of SDH on a 25mm and 50mm radii, respectively.

The Sscans shows the results obtained with a soundpath focalization at 25 and 50 mm . We can see the influence of focalization on the detection of the SDH. If the focal spots are not at the right depths, the SNR is relatively poor.

Distance focusing: the operator specifies the distance from a reference point and the angle of the focalization spots

We look here at the angled row and the vertical column of SDH in the ASTM mockup.

This allows to keep perfect focalization along any line inside the components such as the chamfer of welds.

All these delay laws are available for linear, matrix, DLA and DMA probes allowing inspectors to optimize and adjust the focalization parameters right on the job. And of course you can use up to 64 elements at the same time to improve both lateral resolution and SNR.