rad physics(halflife).docx

Radioactivity

The process by which atoms spontaneously emit high energy particles or rays from their nucleus.

Parent nuclide

The original nuclide which undergoes radioactive decay.

Daughter nuclide

The more stable nuclide which results from radioactive decay.

Alpha particle

A helium nucleus with 2 protons and 2 neutrons, emitted during alpha decay.

Beta particle

A fast moving electron originating from the nucleus, ejected when a neutron changes into a proton.

Gamma ray

Very high energy electromagnetic radiation emitted during nuclear transitions, characterized by high frequency.

Positron

A particle similar to an electron but with a positive charge, emitted during positron decay.

Activity (A)

The number of disintegrations of a nucleus occurring per second in a sample.

Decay constant (λ)

The fraction of atoms which undergo decay per unit time.

Half-life (T 1/2)

The time taken for half the atoms of a radionuclide to undergo radioactive decay.

Alpha decay

A type of decay where heavy nuclei emit an alpha particle, decreasing atomic number by 2 and mass number by 4.

Electron capture

A decay process where an electron is captured by a proton in the nucleus, resulting in a neutron.

Nuclear equation

An equation that shows the transformation of atoms during radioactive decay, balancing mass and charge.

Nuclide

Any atomic species characterized by the number of protons and neutrons.