Transmission Electron Microscope

• What is the full name of TEM?

  Transmission Electron Microscope
• How does a Transmission Electron Microscope (TEM) work?

  It uses electron waves for high resolving power
• When were the first TEMs constructed?

  In the 1930s
• What type of lenses do TEMs use to focus beams of electrons?

  Magnetic lenses
• What happens to electrons in a TEM after passing through a sample?

  They form an image on a fluorescent screen
• What are the functions of the different lenses in a TEM?

  • Condenser lens: Deforms electrons into a parallel beam
  • Objective lens: Forms an image of the sample
  • Projector lens: Magnifies the image onto a fluorescent screen

  
• What does the electron gun in a TEM do?

  It emits electrons through thermionic emission
• How are electrons accelerated in a TEM?

  By a large potential difference
• What is the role of the condenser lens in a TEM?

  It creates a wide parallel beam of electrons
• How does the objective lens function in a TEM?

  It forms an image by deflecting outer electrons
• What does the projector lens do in a TEM?

  It spreads out beams to magnify the image
• What affects the level of detail in a TEM image?

  The resolving power of the microscope
• Why must electrons travel fast in a TEM?

  To achieve the shortest wavelength and highest resolving power
• What happens to electrons as they pass through the sample in a TEM?

  They slow down, increasing wavelength and reducing power
• What is the consequence of electrons having different speeds in a TEM?

  They form a blurrier image on the screen
• How does the speed of electrons affect the image quality in a TEM?

  Different speeds lead to a range of projected locations