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First commercial Electron microscope, constructed by Ernst Ruska in 1939. Ernst August Friedrich Ruska (German pronunciation: [ɛʁnst ˈʁʊskaː] ⓘ; 25 December 1906 – 27 May 1988) [1] was a German physicist who won the Nobel Prize in Physics in 1986 for his work in electron optics, including the design of the first electron microscope.
The nucleus was discovered in 1911, as a result of Ernest Rutherford's efforts to test Thomson's "plum pudding model" of the atom. [10] The electron had already been discovered by J. J. Thomson. Knowing that atoms are electrically neutral, J. J. Thomson postulated that there must be a positive charge as well.
Reproduction of an early electron microscope constructed by Ernst Ruska in the 1930s. Many developments laid the groundwork of the electron optics used in microscopes. [2] One significant step was the work of Hertz in 1883 [3] who made a cathode-ray tube with electrostatic and magnetic deflection, demonstrating manipulation of the direction of an electron beam.
Electron discovered by J. J. Thomson [4] 1899 Alpha particle discovered by Ernest Rutherford in uranium radiation [5] 1900 Gamma ray (a high-energy photon) discovered by Paul Villard in uranium decay [6] 1911 Atomic nucleus identified by Ernest Rutherford, based on scattering observed by Hans Geiger and Ernest Marsden [7] 1919
An account of the early history of scanning electron microscopy has been presented by McMullan. [2] [3] Although Max Knoll produced a photo with a 50 mm object-field-width showing channeling contrast by the use of an electron beam scanner, [4] it was Manfred von Ardenne who in 1937 invented [5] a microscope with high resolution by scanning a very small raster with a demagnified and finely ...
Dr Cliff said the scientists found "what we now call a proton", a building block particle present in all atoms. He said what Rutherford was showing for the first time was "that you can perform ...
Born in Brantford, Ontario, the son of James and Ethel (Cooke) Hillier, he received a Bachelor of Arts in Mathematics and Physics (1937), Master of Arts (1938), and a Ph.D (1941) from the University of Toronto, where, as a graduate student, he completed a prototype of the electron microscope that had been invented by Ernst Ruska.
The electron or positron emissions are called beta particles. Beta decay either increases or decreases the atomic number of the nucleus by one. Electron capture is more common than positron emission, because it requires less energy. In this type of decay, an electron is absorbed by the nucleus, rather than a positron emitted from the nucleus.