Nuclear Radiation Flashcards
Background radiation
Low levels of radiation from environmental sources, always present around us
Decay
A process in which a nucleus’s structure is changed, usually accompanied by the emission of a particle
Alpha
Particles are composed of two protons and two neutrons, the same as a helium nucleus
Beta
An electron emitted at high speed from the nucleus when a neutron decays into a proton
Gamma Rays
High energy, high frequency, electromagnetic radiation, emitted from a nuclear radioactive decay
Decay constant
The probability, per second, that a given nucleus will decay
Activity
The number of radioactive decays in unit time
Half-life
Time taken for half of the atoms of a nuclide within a sample to decay. Alternatively, the time taken for the activity of a sample of a radioactive nuclide to reduce to half its initial value
Mass deficit/Mass defect
The difference between the measured mass of a nucleus and the sum total of the masses of its constituent nucleons
Binding Energy
The energy used to hold the nucleus together, converted from the mass deficit, following E=mc^2
Fusion
Happens when small nuclides combine together to make larger nuclei, releasing energy
Fission
Happens when larger nuclei are broken up into smaller nuclides, releasing energy
Thermal neutron
A relatively slow-moving neutron
Moderator
A material used in a nuclear reactor to slow fast-moving neutrons to thermal speeds
Fuel Rod
Within a nuclear reactor is a rod containing the fissionable material, e.g. Uranium-235
