A positively charged particle made up of two neutrons and two protons It is the least penetrating of the three common forms of radiation, and can be stopped by a sheet of paper
Radiation consisting of helium nuclei (atomic wt 4, atomic number 2) that are discharged by radioactive disintegration of some heavy elements, including uranium-238, radium-226, and plutonium-239
The least penetrating type of nuclear radiation; not considered dangerous unless alpha-contaminated particles enter the body (FEMA-SS)
Alpha rays consist of nuclei of the element helium and carry a positive charge Penetrates the least, but does great damage in a small area (see radiation)
The most energetic but least penetrating form of radiation It can be stopped by a sheet of paper and cannot penetrate human skin However, if an alpha-emitting isotope is inhaled or ingested, it will cause highly concentrated local damage
An emission of alpha particles (helium nuclei) from a material undergoing nuclear transformation
The least penetrating type of nuclear radiation; not considered dangerous unless alpha-contaminated particles enter the body
A type of radiation reulting from the emission of helium nuclei from the nuclei of atoms
Alpha particles can be stopped by very thin absorbing materials, e g : a few sheets of paper, or, 1/64th inch of aluminum foil Since alpha particles travel only short distances in air, and alpha particles up to 7 5 MeV are absorbed by the outer layer of skin (dead tissue), alpha radiation is not considered an external exposure problem
A helium nucleus emitted spontaneously from radioactive elements It is dissipated in a few centimeters of air or less than 0 005 mm of aluminum