| 摘要 |
PURPOSE:To make it possible to detect the shape of an electron beam in a short time by measuring a beam diameter in each direction. CONSTITUTION:A mark is scanned by an electron beam radially from the center of a circle to obtain reflected-electron detection signal (a). As the beam scans the mark from part Cr to part Au, signal (a) changes from a low level to a high level. The beam diameter is equivalent to a time from slice level 1 to slice level 2 and obtained by multiplying the single scanning time of the beam by a coefficient of scanning length. From levels 1 and 2, slice signal (b) is generated and then converted by an intergral network into a voltage to generate signal (c), which is sent to a video part to project the beam diameter as a spot. This operation is repeated to output a beam diameter in each direction to the video part, so that the beam shape can be observed.
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