Ray Diagram of TEM

Electrons are emitted from the electron gun and accelerated by a potential difference (a typical value for HRTEM is 200 to 300kV). These electrons are focused by the condenser lenses to form a parallel beam. The electron beam strikes a 

In comparison with X-rays, an electron beam can have a very short wavelength, which can be calculated according to the equation below when the relativistic correction is considered  

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