Abstract: An orifice plate having orifice openings is interposed between a roller body and a side plate. In a closed region of an outer peripheral surface of the roller body which is covered with a base material, the base material is held on the outer peripheral surface of the roller body under suction by a negative pressure developed in suction holes. In an open region of the outer peripheral surface which is not covered with the base material, the sucking of a gas from an exterior space into the roller body is suppressed because it is difficult for the gas to pass through the orifice openings. This suppresses a reduction in sucking force in the closed region due to the entry of the gas from the open region. The roller body, the orifice plate and the side plate rotate as a unit. This suppresses deterioration of the members due to the slidable movement thereof.

Abstract: An orifice plate having orifice openings is interposed between a roller body and a side plate. In a closed region of an outer peripheral surface of the roller body which is covered with a base material, the base material is held on the outer peripheral surface of the roller body under suction by a negative pressure developed in suction holes. In an open region of the outer peripheral surface which is not covered with the base material, the sucking of a gas from an exterior space into the roller body is suppressed because it is difficult for the gas to pass through the orifice openings. This suppresses a reduction in sucking force in the closed region due to the entry of the gas from the open region. The roller body, the orifice plate and the side plate rotate as a unit. This suppresses deterioration of the members due to the slidable movement thereof.

Abstract: In a eucentric side entry goniometer stage used in an electron microscope controlled in five-axes of specimen positions (x, y, z) and specimen tilt angles (.theta..sub.x, .theta..sub.y), image shifting during tilting a specimen is automatically corrected. Assuming that the coordinates of an observed point are (x, y, z), shifting of observed image is automatically corrected by calculating correction values of image shifting .DELTA.y and .DELTA.z using a calculator based on the following equations and by shifting the observed point to a coordinates (x, y-.DELTA.y, z-.DELTA.z) using a specimen position and tilt angle controller when the tilt angle .theta..sub.y is varied from .theta..sub.y1 to .theta..sub.y2 wherein.DELTA.y=y(1-cos .theta..sub.y2 /cos .theta..sub.y1).DELTA.z=y(sin .theta..sub.y2 -sin .theta..sub.y1)/cos .theta..sub.y1.

Abstract: An electron microscope comprising an electron gun for generating an electron beam, an irradiation lens system for irradiating a specimen with the electron beam, means for obtaining an image signal of the specimen, a frame memory for storing the image signal, means for obtaining a total accumulation function, which indicates the sum total of accumulated values in a plurality of one-dimensional directions, and in which each of the accumulated values in the plurality of one-dimensional directions indicates accumulation with respect to a frequency of a function obtained by applying one-dimensional Fourier transform to a function obtained by projecting two-dimensional intensity distribution of said image signal in corresponding one-dimensional direction thereof, and means for obtaining a substantial extreme point of the total accumulation function.