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:
“For me, the principal fact of life is the free mind. For good and evil, man is a free creative spirit. This produces the very queer world we live in, a world in continuous creation and therefore continuous change and insecurity. A perpetually new and lively world, but a dangerous one, full of tragedy and injustice. A world in everlasting conflict between the new idea and the old allegiances, new arts and new inventions against the old establishment.”
—Joyce Cary (1888–1957)
“One of the necessary qualifications of an efficient business man in these days of industrial literature seems to be the ability to write, in clear and idiomatic English, a 1,000-word story on how efficient he is and how he got that way.... It seems that the entire business world were devoting its working hours to the creation of a school of introspective literature.”
—Robert Benchley (1889–1945)
“Today, each artist must undertake to invent himself, a lifelong act of creation that constitutes the essential content of the artist’s work. The meaning of art in our time flows from this function of self-creation. Art is the laboratory for making new men.”
—Harold Rosenberg (1906–1978)