Types and Production
Particles can be electrically charged or uncharged:
Particle radiation can be emitted by an unstable atomic nucleus (radioactive decay) in the form of a positively charged alpha particle (α), a positively or negatively charged beta particle (β) (the latter being more common), a photon (called a gamma particle, γ), or a neutron. Neutrinos are produced in beta decay in addition to beta particles; they interact with matter only very weakly. Photons, neutrons, and neutrinos are uncharged particles. The decay events of proton emission and cluster decay also emit (groups of) nucleons as charged particles, but are comparatively rare.
Other forms of particle radiation, including mesons and muons, occur naturally when (cosmic rays) impact the atmosphere. Mesons are found at high altitudes, but muons can be measured even at sea level.
Charged particles (electrons, mesons, protons, alpha particles, heavier atomic ions, etc.) can be produced by particle accelerators. Ion irradiation is widely used in the semiconductor industry to introduce dopants into materials, a method known as ion implantation.
Particle accelerators can also produce neutrino beams. Neutron beams are mostly produced by nuclear reactors. For the production of electromagnetic radiation, there are many methods, depending upon the wave length (see electromagnetic spectrum).
Read more about this topic: Particle Radiation
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—Anton Pavlovich Chekhov (1860–1904)
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—Albert Camus (1913–1960)
“It is part of the educator’s responsibility to see equally to two things: First, that the problem grows out of the conditions of the experience being had in the present, and that it is within the range of the capacity of students; and, secondly, that it is such that it arouses in the learner an active quest for information and for production of new ideas. The new facts and new ideas thus obtained become the ground for further experiences in which new problems are presented.”
—John Dewey (1859–1952)