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The ‘’ tubes’’ in Radiology
Click here to see our objects about tubes Click here to see other information about tubes ( HAKIM'S COLLECTION ). 1) Cathodic tubes Long before the discovery of the X-rays , in 1855 H.GEISSLER (1814-1879) was successful in manufacturing the first rare gas tube. Relative Vacuum "GEISSLER" (0-516) When the pressure in the tube was reduced to about a hundredth of the atmospheric pressure , a bright band of violet light appeared between the electrodes . The invention of the mercury air pump in 1865 by H.SPRENGEL (1834-1906) (0-496) , made it possible in 1878 for Sir W. CROOKES (1832-1919), to study electrical discharges in rarefied gases at pressures as low as one millionth of an atmosphere . High Vacuum ‘’CROOKES’’ (0-398) As the pressure is reduced still further , another phenomenon occurs, first observed in 1869 by J. HITTORF (1824-1914) . Faint blue rays arise from the cathode , which produce a bright light (fluorescence ) when they impinge on the glass wall of the tube . These rays were given the name cathode rays or cold cathode tube rays in 1876 by E .GOLDSTEIN (1850-1930) Finally O.SCHOTT( 1851-1935) succeeded in 1894 in increasing the resistance of the glass wall of the tubes. In 1894, Ph. LENARD (1862-1947) was the first one to see the cathode ray image on a few millimetres out of the tube wall despite the aluminium sheet covering the glass. (0-522) W.C. RÖNTGEN ( 1845-1923 ) in november 1895 discovered unknown rays coming out of the discharge tube :that he called X-rays .When he immobilized for some moments his hand in the path of the rays on top of a photographic plate he could see the bone structure after development of the plate . RADIOLOGY was born. (O-410) |