Our best ever peak sensitivity of a pair of air-coupled ultrasonic transducers: -17 dB!
This amazing and unrivalled figure is obtained with the pair of focused 250 kHz trasnducer (of the sph75 series) having focal distance at 65 mm and a 6dB-focal spot of 4mm diameter. Results shown in the figure were obtained using an Olympus 5077 P/R, 100 V excitation (semicycle square wave, no gain in reception). Tx and Rx in confocal configuration: separation 130 mm. This amazing sensitivity allow us to fast inspect in through trasnmission mode thick sandwich curved components with asymetric CFRP skins and thick honeycomb core without averaging and using the DASEL difrascope P/R (400 V, toneburst excitation).
Ultrasounds for Biological Applications and Materials Science 