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radioactive particle
subject			fact

radioactive particle	has desintegration energy the total energy produced when the particle decays
	has decay products the products produced immediately after decay
	has lifetime The average time in which a particle decays
	has definition A particle which can produce harmful radioactivity directly through its decay or by interacting with other particles.
	is a kind of particle
particle	obeys uncertainty principle
	has frequency inversely proportional to the wavelength
	has wavelength inversely proportional to its momentum
	has charge
	has mass
physical object	has location or center of gravity
	has angular momentum
	has velocity
	has momentum
	has temperature
	has volume
	has extent
	has material

Kinds of radioactive particle :

• antineutron (6 facts) - The antiparticle of a neutron. A neutron and antineutron both have the same mass and zero electric charge, but can be differentiated by their interactions: a neutron and an antineutron can annihilate into gamma rays, while two neutrons cannot.
• antiproton (7 facts) - The antiparticle of a proton, identical in mass and spin but of opposite (negative) charge.
• cosmic rays (6 facts) (corpuscular radiation) - High-energy charged particles which stream at relativistic velocities down to Earth from space. The Sun ejects low-energy (10⁷ - 10¹⁰ eV) cosmic rays during solar flares (those of lower energy than this are unobservable from Earth because of solar system magnetic fields). Those of intermediate energy (10¹⁰ - 10¹⁶ eV) have an isotropic distribution, and are apparently produced in the Galaxy. Possible sources of acceleration are shock waves accompanying supernovae (although cosmic rays have a higher hydrogen content than would be expected from a star that has processed material to iron), and the rotating magnetic fields of pulsars. The light elements Li, Be, and B have a higher abundance ratio in cosmic rays than in the solar system.
• hyperon (4 kinds, 17 facts) - Baryons heavier than the neutron (this term is seldom used today). They have non-zero strangeness. Free hyperons are unstable and decay into end products, one of which is a proton.
• muon (9 facts) (μ) - A second-generation lepton. It is essentially a more massive electron., Short-lived elementary particle with negative electrical charge. Muons are leptons. They resemble electrons, but are 207 times more massive., An elementary particle, formerly called a mu-meson but now classified with the leptons because it seems to be identical with the electron except for its much greater mass (207 times that of an electron). The muon family includes the muons and their neutrinos (and their antiparticles). Muons may have a positive or a negative charge., Elementary particles produced when cosmic rays enter the upper atmosphere.
• neutron (14 facts) - Particle in the nucleus of all atoms except hydrogen. Through beta decay, a neutron may become a proton and an electron; the process occurs in reverse during the formation of a neutron star., One of the constituents of the atomic nucleus discovered in 1932. It is bound into atomic nuclei by the strong nuclear force. Free neutrons decay slowly via the weak nuclear force. Despite being electrically neutral, the neutron possesses both an electric dipole moment (as if it were made of positive and negative charges separated a minute distance) and a magnetic moment, indicating some internal substructure., A neutral baryon., A nuclear particle with a mass slightly greater than that of a proton. A free neutron decays, after a half-life of about 10.6 minutes, into a proton, an electron, and an antineutrino. The neutron is probably made up of still more fundamental particles having both positive and negative charges. The charges balance to give a net charge of zero, but the motions of the charges are such that their magnetic contributions do not cancel and consequently the neutron is magnetic., typically found in the nucleus of an atom., Stable within the nucleus, the neutron if isolated decays, with a ha half-life of fifteen minutes.
• positron (10 facts) (antielectron) - The antiparticle of the electron, discovered by Anderson in 1934. It has the same mass and spin as the electron, but opposite charge and magnetic moment.
• positronium (4 facts) - A positron and electron bound together electrostaticaly.
• radioactive element (20 kinds, 319 facts) - an unstable radioactive element which has an excess or deficit of neutron relative to the stable element
• tau (5 facts) (τ)
• triton (6 facts) (T) - The nucleus of the tritium atom.

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