Bandwidth-Dependent DAC Curves

Abstract

Defect sizing using Distance Amplitude Correction (DAC) curves gets very time consuming when using phased array angle beam probes. For each incidence angle applied during testing a DAC/TCG curve has to be recorded. By changing the phasing angle important probe parameters such as near field length, delay line length and sensitivity are changed as well, resulting in a change of the DAC/TCG curve. DAC curves can be calculated using the new probe technology. It is sufficient to just measure one reference echo, e.g., using a calibration standard. The DAC curves for all angles can be calculated. Alternatively a DAC curve can be recorded using one single angle of the phased array angle beam probe. By recording the curve for one single angle the material characteristics of the reference block such as the sound attenuation are considered automatically. The DAC curve for all other angles are calculated with high accuracy. With the new probe technology recording DAC curves for phased array angle beam probes is as easy as recording a DAC curve with a single element angle beam probe.