| 摘要 |
PURPOSE:To obtain the charged particle radiation of arbitrary cross-sectional form including a triangle by a method wherein an aperture of a right-angled equilateral triangle is provided in four slits which are the irreducible minimum number, two sheets of slits are selected by adjusting the excitation of an image- forming lens, and the degree of overlapping of the triangular aperture of each slit is adjusted by a deflector. CONSTITUTION:Triangular apertures A1, A2, A3 and A4 are perforated on slits 3, 5, 10 and 11, and said triangle is arranged in advance in such a manner that it faces the prescribed direction taking into consideration of the rotation and the like of an image by a lens. The triangle is a right-angled equilateral triangle consisting of two sides which are orthogonally intersecting with each other and a side intersecting at the angle equal to that of the above-mentioned sides. Two sheets of slits are arbitrary selected from these slits by properly regulating the intensity of excitation of lenses 4, 12 and 13. The beam, having the desired shape, namely, a rectangle, a parallel tetragon and a triangle, and the size of cross-section can be obtained by adjusting the degree of overlapping of the image of electrons passed the aperture of the slit on the upper stage of the two slits and the aperture of the slit on the next stage.
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