Creation
Charged particles such as electrons, positrons, and protons may be separated from their common surrounding. This can be accomplished by e.g. thermionic emission or arc discharge. The following devices are commonly used as sources for particle beams:
- ion source
- cathode ray tube, or more specifically in one of its parts called electron gun. This is also part of traditional television and computer screens.
- photocathodes may also be built in as a part of an electron gun, using the photoelectric effect to separate particles from their substrate.
- Neutron beams may be created by energetic proton beams which impact on a target, e.g. of beryllium material. (see article Particle therapy).
Read more about this topic: Particle Beam
Famous quotes containing the word creation:
“I do not, like the Fundamentalists, believe that creation stopped six thousand years ago after a week of hard work. Creation is going on all the time.”
—George Bernard Shaw (1856–1950)
“Some collaboration has to take place in the mind between the woman and the man before the art of creation can be accomplished. Some marriage of opposites has to be consummated. The whole of the mind must lie wide open if we are to get the sense that the writer is communicating his experience with perfect fullness.”
—Virginia Woolf (1882–1941)
“If we admit a thing so extraordinary as the creation of this world, it should seem that we admit something strange, and odd, and new to human apprehension, beyond any other miracle whatsoever.”
—George Berkeley (1685–1753)