The pressure-pulse method for measuring space-charge distribution in irradiated insulators

The authors report on the determination of the spatial charge distribution in electron-irradiated Teflon films by the pressure-wave-propagation method. A pressure pulse generated in the sample by a Nd-YAG pulsed laser is used as a virtual probe of the charge distribution. The authors show that positive charges are injected at the metal/dielectric interface. The charges remain trapped after a surface discharge, but buried incident electrons disappear. The method could also be applied to insulators used in a vacuum.<
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