The scanning electron microscope (SEM) is commonly used to obtain images of a wide variety of samples within a wide range of magnification factors from the order of 10 up to about 105×. This technique is usually applied, but not limited to, the investigation of conductive samples. This is because the interaction of the scanning beam with the sample generates a net charge on the sample surface. Thus, if the sample is conductive, the charge can be quickly disposed of to ground, away from the beam spot. If the sample in non-conductive, the sample becomes locally charged, giving rise to a distortion of the primary beam. In certain conditions, the charge stored on the sample is able to reflect back the incoming electrons, much like an electrostatic mirror.