Lab Equipment for Teaching Physics

Features

• Long lifetime electron diffraction tube

• Clear & sharp diffraction rings

  
  

• Well isolated high-voltage and low-voltage

• High measurement accuracy

  
  

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Introduction

In the early 20th century, the dual nature of light—exhibiting both wave and particle properties—was already established. In 1924, the French physicist Louis de Broglie proposed the hypothesis that all microscopic particles possess wave-particle duality. This idea was experimentally confirmed in 1927 by American physicists Clinton Davisson and Lester Germer, who observed electron diffraction when electrons were reflected from a crystalline nickel target. Their experiment provided direct evidence for de Broglie’s hypothesis, demonstrating that electrons behave not only as particles but also as waves. Shortly afterward, British physicist G.P. Thomson performed a complementary experiment by passing electrons through a thin crystalline film, further confirming the wave nature of electrons through the measurement of their de Broglie wavelength. Today, electron diffraction has developed into a powerful technique for investigating thin solid films and the surface structure of crystals.

The LEAI-62 Electron Diffraction Apparatus is designed to demonstrate these fundamental principles with clarity and precision. The system is equipped with a specially designed diffraction tube, visible through a transparent side window of the apparatus. Inside, an electron gun capable of sustaining high voltage and long-term operation directs an electron beam toward a thin polycrystalline gold foil target positioned between the gun and the fluorescent screen. The electrons are accelerated by a voltage of up to 20 kV, producing a distinct diffraction pattern upon striking the metallic target. The resulting pattern is bright, sharp, and well-defined on the screen, allowing students not only to observe the phenomenon qualitatively but also to perform accurate quantitative measurements.

The accompanying instruction manual offers comprehensive materials, including experimental configurations, theoretical principles, and step-by-step instructions, ensuring that students can effectively use the system for their experiments. Please click Experiment Theory and Contents to find more information about this apparatus.

Using this instrument, the following experiment objectives can be achieved::

1. Acquire the wavelength of a moving electron, and verify the de Broglie equation.

2. Measure the lattice constant of gold crystalline material.

3. Measure the Miller indices of corresponding diffraction rings.

4. Calculate the Planck's constant.

Specifications