The Röntgen Radiation and its application in studies of ... - Mansic

In this radiography the hand bones show up very obvious, just as the ring that
his wife was wearing on her finger. On the day of March 28th 1895, Röntgen
presented his results to the Medical-Physical Society from Wurzburg. In the
course of a few days, the experiments of Röntgen were repeated in numerous
laboratories around the world and after a few weeks attempts were made to use
the X rays in medicine. After a couple of months from the discovery of X-rays, the
Romanian physicist Dragomir Hurmuzescu (1865-1954) built a very sensitive
electroscope, that was named after him, especially for the study of these
radiations. This electroscope has proved to be very useful for the study of
ionisation phenomenons caused by different radioactive substances. Röntgen’s
discovery became famous in a very short time.
Almost all scientific journals were preoccupied on it. Indeed what could be more
amazing than its invisibility for the human eye? Such property can be used to
“see” the skeleton of a human body and other animals. Of course, one cannot
deny that Röntgen had a struck of luck when he discovered the X rays. Other
physicists have had a chance, but they didn’t know how to take advantage of that.
In the book “The History of the Ether and of the Matter Theories”, Whittaker tells
of a physicist from Oxford who had realized that a latent image forms on the
photographic plates only when they are close to a gas discharge tube. He found
that X-rays are emitted by the part of a tube which is bombarded by electrons
obtained from a cathode. Based on this observation, Röntgen built a generator
and the tube, which provides the most favorable way for obtaining and using
X - rays. Röntgen knew that cathode rays leave the cathode along a normalised
direction Based on this he built a concave cathode that focused the emitted beam
in one point. Because most of the energy brought by cathode rays turn into a
heat strongly increasing temperature of the anode, presenting even the danger of
melting it, Röntgen introduced in the tube a special plate made from heat
resistant material, on which he focused the beam.
This plate, that was given the name of anticathode, was placed at an angle of 45º
from the axle of the tube in order to make the use of the emitted X-rays more
comfortable. This way, Röntgen built the tube that bears his name and which
construction remained essentially unchanged until today.
Physics of Advanced Materials Winter School 2008 2