A Charge Microscopy for High Temperature Use with a Polymer Acoustic Coupler

In the insulation technology, complex systems including heterogeneous interfaces are often handled, and it is desirable to measure the electric field distortion and its dynamic change due to space charge spreading in two or three dimensions. A well-known scanning device for this purpose was proposed by Maeno et al. based on the pulsed electro-acoustic method. To detect acoustic signals generated by electric charges, a metallic acoustic coupler, which also serves as an electrode, coupled to the water medium. An aspherical acoustic lens was used to compensate for large aberrations. The presenter fabricated an acoustic coupler made of a polymer whose sound velocity is close to that of water to reduce aberration problems. The high thermal resistance of the polymer acoustic coupler was utilized to enable measurement at temperatures exceeding 100°C.