Analytical electron microscope

摘要

An analytical electron microscope directs an electron beam onto a specimen. The beam is switched back and forth between two states in one of which the beam is finely focused to a size on the order of nanometers. In the other the beam is defocused to a size on the order of microns. A magnified image of a relatively broad region on the specimen irradiated with the defocused beam and a bright spot image are alternately displayed on a fluorescent screen. The bright spot image is obtained from a region on the specimen irradiated with the focused beam. The two images are displayed alternately at intervals shorter than the persistence time of the fluorescent screen to permit one to observe both images simultaneously. The operator moves the position at which the beam irradiates the specimen to bring the bright spot image into a desired region to be analyzed while observing the two images. Thus, the focused beam irradiates the specimen at the desired region. The resulting X-rays are detected, or a diffraction image produced in response to the irradiation of the focused beam is photographed.