The Roentgen rays in medicine and surgery as an aid in diagnosis and as a therapeutic agent : designed for the use of practitioners and students (1901)
Williams, Francis H. (Francis Henry), 1852-1936 · New York, Macmillan · leaf 86
cium Screen.—Certain of the tungstate of calciumscreens are phosphorescent as well as fluorescent — that is, in a darkroom they retain the image of an object opaque to the rays for a momentafter the tube has been shut off. They should therefore be tested inthe following way before being purchased :… … Fig. 47. Tube holder closed and ready for use. the tube with a dark cloth, or by placing it in the box already described.A piece of heavy metal should then be placed under the fluorescentscreen and held in the same position-for a minute or two. While thephysician is thus observing the screen, the…
Radiography · X-rays
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