: Hübschen, G.; Neuschwander, R.; Salzburger, H.J.; Wilbrand, A.

Abstract
The state of the art of the EMUS (electromagnetic-ultrasonic) system technology is illustrated presenting as examples two typical systems, an 8-channel phase array system for ultrasonic inspections in the field especially of the primary circuit of nuclear power plants, and a 2-channel standard system. The phased array technique provides a significant enhacement of the signal-to-noise ratio and the bandwidth, suppression of the sensitivity in the backward direction of the ultrasonic probe, and allows electronic setting and changing of the angle of incidence at a fixed frequency. Production costs of EMUS systems will be reduced by modular design of all electronic components. Miniaturization using SMD and PAL technology will alow to build e.g. a 8-channel phased array system housing with a height of 150 mm. Miniaturized EMUS probes allow new applications of the EMUS technique utilizing Rayleigh waves, shear horizontal waves, and normally incident linearly polarized shear waves.