The Maltese cross has no external electrical connection.Ĭathode rays are so named because they are emitted by the negative electrode, or cathode, in a vacuum tube. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.Ī diagram showing a Crookes tube connected to a high voltage supply. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. They were first observed in 1869 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitted from the cathode (the electrode connected to the negative terminal of the voltage supply). Cathode rays are normally invisible in this demonstration with a Teltron tube, enough gas has been left in the tube that the gas atoms luminesce when struck by the fast-moving electrons.Ĭathode rays ( electron beam or e-beam) are streams of electrons observed in discharge tubes. Both very good condition.A beam of cathode rays in a vacuum tube bent into a circle by a magnetic field generated by a Helmholtz coil. Ex-libris with stamps on front wraps professionally rebacked at the spine (see scan). Item #694 CONDITION & DETAILS: Two issues in original wraps. “Whereas his father had seen the electron as a particle (and won his Nobel Prize in the process), Paget Thomson demonstrated that it could be diffracted like a wave, a discovery proving the principle of wave-particle duality which had first been posited by de Broglie in the 1920s as what is often dubbed the de Broglie hypothesis” (Strickland, Creators of Quantum Physics, 180). In particular, the relation that the size of the rings is in all cases inversely as the momentum of the cathode rays is fully confirmed, and the number and size of the rings correspond remarkably with what is to be expected from the known crystalline structure of gold and aluminium, using de Broglie’s expression for the wave- length of the cathode rays” (Abstract). In the paper of 1927 December, Paget Thomson (working alone) confirmed and extended his experimentation “to films of gold, aluminium, and of an unknown (probably organic) substance. These were attributed to a diffraction of the cathode rays by the film, the cathode rays behaving as waves of wave-length h/mv according to de Broglie’s theory of wave mechanics, and regularities in the structure of the film, or in the size of the molecules, making it behave as a kind of diffraction grating” (Abstract). In the first paper offered here (June 1927), Reid and Paget Thomson describe “the rings formed when a beam of cathode rays was sent at normal incidence through a thin film of celluloid and struck a photograph plate placed some distance behind the film. “Reasoning that the effect would be easier to analyze with a solid than with a gaseous target, Thomson asked one of his students, Alexander Reid, to modify an existing apparatus and investigate the scattering of a beam of electrons with energy in the keV range through this celluloid films at normal incidence” (Lindau). In 1924, the de Broglie hypothesis argued that a wave must be associated with the motion of any material corpuscle. It is at Aberdeen that Paget Thomson began to carry out experiments revealing the phenomena of electron diffraction with thin metal foils and high-voltage electrons.

Following a post at Cambridge, Paget Thomson became Professor of Natural Philosophy at the University of Aberdeen.

Paget Thomson studied at Cambridge’s Trinity College, later working for a year studying atomic structure with his father this was followed by work at Cavendish Laboratory until WWI.

Sir George Paget Thomson was born in 1892, the son of the physicist Sir J. The experiments conducted here “beautifully confirmed the wave theory” (Lindau Nobel Laureate Portal). FIRST EDITION IN ORIGINAL WRAPS OF THOMSON & REID’S NOBEL PRIZE WINNING PAPERS “for the experimental discovery of the diffraction of electrons by crystals” (Nobel Prize Portal).

Thomson cathode ray experiment