In order to perform this comparison measurements have been carried out in a 50 mm thick mock-up containing three SDH (Ø 2 mm, Ø 1.5 mm, Ø 1 mm and 60 mm long) and one FBH (Ø 3 mm tilt 45°) at 30 mm depth.
- Amplitude analysis: for a given probe, the measured and simulated maximum amplitude of the specular echo of the three SDH and of the FBH are compared. The FBH is used for amplitude calibration. The aim of these measurements is to perform an experimental validation of the SDH simulation by using a FBH as calibration reflector.
- A-scan analysis: in some cases, the A-scans are also stored, which enlightens the creeping wave around the SDH.
The measurements are performed with contact mono-element and phased-array probes in pulse echo mode. The parameters of the probes are given in the following tables.
Mono-element probes:
| Frequency | Crystal | Mode | Calibration |
| 2.25 MHz | Ø6.35 mm | SV45° | Ø3 mm FBH |
| Ø12.7 mm | P45° | Ø3 mm FBH | |
| Ø12.7 mm | SV45° | Ø3 mm FBH |
Phased-Array probe:
| Frequency | Elements | Pitch | Wedge angle (incidence) | Focal laws |
| 5 MHz | 20 | 0.7 mm | 21° (refracted P66° and SV30°) | Beam steering P45° |
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