APPARATUS FOR IMPROVING THE SIGNAL INFORMATION IN THE EXAMINATION OF SAMPLES BY SCANNING ELECTRON MICROSCOPY OR ELECTRON PROBE MICROANALYSIS

摘要

In the analysis of a sample bombarded by a scanning primary electron beam, in order to ensure that only low-energy electrons emitted by the sample contribute to the image formation in an evaluating apparatus, adjacent the sample face an alternating electric or magnetic field is generated which periodically weakens the current of electrons emitted by the sample so that a modulated electron flow reaches a secondary electron detector disposed in the vicinity of the sample.