. A text book of physics, for the use of students of science and engineering . sub- nice a new fo m of radiation is emitted. This radiati n has greatpenetrating power and produces photographic and electrical was discovered by Eontgen and was called by him X rays. Amodern form of X-ray tube is shown in Fig. 982. It is exhausteduntil the Crooks dark space is larger than the tube itself, so thatthere is no kathode glow present. The kathode K is of aluminium and is concave, so that the kathode LXXX X-RAYS 1033 rays come to a focus at a small spot upon a sheet of platinum Bplaced at an a
. A text book of physics, for the use of students of science and engineering . sub- nice a new fo m of radiation is emitted. This radiati n has greatpenetrating power and produces photographic and electrical was discovered by Eontgen and was called by him X rays. Amodern form of X-ray tube is shown in Fig. 982. It is exhausteduntil the Crooks dark space is larger than the tube itself, so thatthere is no kathode glow present. The kathode K is of aluminium and is concave, so that the kathode LXXX X-RAYS 1033 rays come to a focus at a small spot upon a sheet of platinum Bplaced at an angle of 45° to the axis of the kathode. B is some-times called the antikathode and is connected to an aluminiumanode A. The presence of A is not essential. The X-rays arise from the small spot upon B, upon which thekathode rays impinge. They have so great a penetrative powerthat they pass through the walls of the tube. Their presence maybe detected by the fluorescence they produce in certain platino-cyanide is one of the best substances for this purpose,. Fig. 982.—Production of X-rays. and it is usually spread upon a cardboard screen C. On looking atthe side D upon which the fluorescent material is spread, a paleblue fluorescence due to the X-rays may be seen. The penetrative power of the X-rays depends upon the vacuumin the tube and also upon the density of the material through whichthey are passing. Thus the higher the vacuum, the greater thepenetrative power of the X-rays. With very high vacuum and greatpenetrative power of the X-rays, these are said to be hard reverse are said to be soft X-rays. Since the penetrative powerdepends upon the density of the material, a body such as E(Fig. 982), placed in the path of the X-rays will cast a shadow uponthe screen, indicating the variation in density of structure of thebody. If the body E be the human hand, the bona? being dense,obstruct the rays and cast a dense shadow. The fleshy parts are 1034 MA
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishe, booksubjectphysics
