Klinger Scientific Diffraction Tube S 

The following topics can be discussed with this highly evacuated tube: 
•  Illustration of the wave nature of electrons
•  Determination of the wavelength of electrons depending on the anode voltage
•  Debye-Scherrer diffraction
•  Confirmation of the de Broglie hypothesis

The electron diffraction tube is a highly evacuated tube with an electron gun consisting of a pure tungsten heater filament and a cylindrical anode all contained in a clear glass bulb. The electrons emitted by the heated cathode are constrained to a narrow beam by an aperture and are then focussed by means of an electron-optical system. The resulting tight, monochromatic beam then passes through a micro-mesh nickel grating situated at the aperture of the gun. Onto this grid, a thin layer of polycrystalline graphitised carbon has been deposited by vaporisation. This layer affects the electrons in the beam much like a diffraction grating. The result of this diffraction is seen in the form of an image comprising two concentric rings that become visible on the fluorescent screen. A spot resulting from the undeflected electron beam continues to be visible at the centre of the rings.
A magnet is also supplied with the tube. This allows the direction of the electron beam to be changed, which may be necessary if the graphite target has slight damage as a result of the manufacturing process or due to later overheating.