| 摘要 |
533,697. R÷ntgen-ray apparatus. PHILIPS LAMPS, Ltd. Nov. 15, 1939, No. 30141. Convention date, Nov. 18, 1938. Addition to 530,477. [Class 98 (i)] A modification of the method of obtaining X-ray images of a section of a body forming the subject of the parent Specification consists in avoiding the necessity o forming a series of strip-forn pictures, which have sub sequently to be trans versely enlarged and superimposed, by moving the sensitive surface during the exposure of each image relatively to the beam in a direction normal to the plane of section of the body, the images so widened being superposed with angular displacements between them produced by rotating the sensitive surface about a fixed point to the same extent as it is rotated about an axis of the body, normal to the plane of section. In the apparatus shown X-rays, originating at the point 1 and limited by a slit 4 to a narrow beam traversing a section of the body 2, are received on a film 5 held on the surface of a cylinder 6, which during exposure is rotated on its axis so that the film receives an image consisting of a lateral expansion of the strip-image formed by the slit. The X-ray source 1 and the cylinder 6 are then rotated through a small angle about the axis 10 of the body, and the film 5 is rotated through the same angle about the axis 1-9, the exposure being them repeated. As explained in the parent Specification, the superposition on the film of a number of images made in this way from angular positions extending all round the body 10 gives a picture of the cross-section. The movements may be made continuous, as in the apparatus shown in Fig. 5, in which the film is secured to a flexible plate 12 held to the surface of the cylinder 11 by channel members 13 engaging its edges, so that it may be rotated by a shaft 14 driven by gears operated by a fixed worm 17 on a stub shaft on which one end of the cylinder is journalled. The ratio of the revolutions of the plate 12 to those of the cylinder 11 may suitably be 1 to 1200.
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