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:
“The very austerity of the Brahmans is tempting to the devotional soul, as a more refined and nobler luxury. Wants so easily and gracefully satisfied seem like a more refined pleasure. Their conception of creation is peaceful as a dream.”
—Henry David Thoreau (1817–1862)
“Poetry, at all times, exercises two distinct functions: it may reveal, it may unveil to every eye, the ideal aspects of common things ... or it may actually add to the number of motives poetic and uncommon in themselves, by the imaginative creation of things that are ideal from their very birth.”
—Walter Pater (1839–1894)
“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)