# Electron Diffracton tube

# Electron Diffracton tube

TEL-2555-2

With the Electron Diffraction Tube one can verify the de Broglie hypothesis and establish the dual nature of the electron. In addition, one can calculate the interatomic spacings of carbon, (the diffracting material in the tube).

TEL-2555-2

The Electron Diffraction Tube emits from an indirectly heated, oxide coated cathode, a narrow converging beam of electrons. The inside surface of the end of the tube has a luminescent screen deposited on it. A micro mesh nickel grid, onto which graphite has been deposited, lies across the exit aperture of the electron “gun”. As the electron beam penetrates this carbon target, the electrons are diffracted into two rings corresponding to separations of the carbon atoms. One can show that the wavelength of an electron λ=d sinθ. Additionally, from the geometry of the tube (see figure 2), we see that θ=D/2L where θ≈sinθ for small angles, D is the diameter of the ring and L is the length from the graphite target to the luminescent screen. Combining the two equations one can show that the diameter of the rings is proportional to (V)^(-1/2). (Rings enhanced for photo demonstration.)