Wilhem Röntgen . Germany scientist and professor in physics.
X-ray of his wife
Before the discovery of the X-rays an invention worked by Willian Crookes about electricity in tubes was essential for X-rays of Röntgen.
After covering the tube with a black cardboard to eliminate visible light, he observed a faint green glow from a screen with a layer of platinum-barium cyanide, which disappeared when the tube was turned off. He determined that the rays created a very penetrating, but invisible, radiation that went through great thicknesses of paper.
He made the first human radiography, using his wife's hand. He called them "incognito rays", or "X-rays" because he did not know what they were, only that they were generated by cathode rays when hitting certain materials.
The news of the discovery of X-rays spread very quickly in the world.
The X-Rays its a great tool to detect diseases.