secondary emission

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secondary emission

A scientist observes secondary emission in a vacuum tube experiment.

Definition

Noun: - The emission of electrons from a surface that is bombarded by higher energy primary electrons: A physical phenomenon where a material, when struck by a beam of energetic particles (primary electrons), releases its own electrons.

Usage
  • This term is used primarily in physics and engineering contexts to describe a specific electron emission process.
  • It is often discussed in relation to the operation of devices like photomultiplier tubes, certain types of vacuum tubes, and in surface science.
Examples
  • Noun:
    • The efficiency of the photomultiplier tube depends on the secondary emission from its dynodes.
    • Scientists studied the secondary emission from the metal surface to understand its electronic properties.
Advanced Usage
  • "Secondary emission coefficient": A key parameter representing the average number of secondary electrons emitted per incident primary electron.
    • A material with a high secondary emission coefficient is chosen for the dynode.
  • "Secondary emission yield": Essentially synonymous with the secondary emission coefficient, describing the ratio of emitted secondary electrons to incident primary electrons.
Variants and Related Words
  • Secondary electron (n): An electron emitted via the process of secondary emission.
    • The detector collects the secondary electrons to form an image.
  • Primary electron (n): The initial, higher-energy electron that causes secondary emission upon impact.
    • The beam of primary electrons is focused onto the sample.
Synonyms
  • Secondary electron emission: A more explicit, full-term synonym.
Related Phrases
  • To result from secondary emission: To be caused by this process.
    • The amplified signal results from secondary emission within the tube.
  • To exhibit secondary emission: To show or demonstrate this property.
    • The coated surface exhibits strong secondary emission.
Notes
  • "Secondary emission" is a compound noun where "secondary" modifies "emission" to specify the type. The core concept explained is the entire phrase.
  • It is distinct from thermionic emission (electron emission due to heat) and photoelectric emission (electron emission due to light).
secondary emission

A scientist observes secondary emission in a vacuum tube experiment.

Noun
  1. the emission of electrons from a surface that is bombarded by higher energy primary electrons