Chapter 2: Radiation Physics

Matter

Anything that occupies space and has mass. fundamental unit is the atom

Nucleus

The central part of an atom, made up of protons and neutrons.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A particle found in the nucleus of an atom that carries no electric charge.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Atomic Number

The number of protons in the nucleus of an atom, which determines the element's identity.

Mass Number

The total number of protons and neutrons in the nucleus of an atom.

Electron Shell

A defined path around the nucleus in which electrons are found.

Binding Energy (electrostatic force or attarction)

The energy required to keep an electron in its orbit; varies with the shell's distance from the nucleus.

Ion

An atom that has gained or lost one or more electrons and is electrically charged.

Ionization

The process of converting an atom into ions through the removal or addition of electrons.

Radioactivity

The process by which unstable atomic nuclei undergo spontaneous disintegration, emitting particles or rays.

Ionizing Radiation

Radiation capable of producing ions by removing electrons from atoms.

Particulate Radiation

Radiation composed of particles, including alpha and beta particles.

Electromagnetic Radiation

The propagation of wavelike energy through space or matter, exemplified by x-rays.

General Radiation

Also known as braking radiation; produced when electrons are slowed by interactions with the nucleus.

Characteristic Radiation

Produced when a high-speed electron dislodges an inner-shell electron from an atom. Accounts for a very small part of x rays produced in the dental x ray machine. it occurs only at 70kv and above

Primary Radiation

The x-ray beam produced at the target of the anode that exits the tubehead.

Secondary Radiation

X-radiation created when the primary beam interacts with matter.

Compton Scatter

When an x-ray photon collides with an outer-shell electron, ejecting it and scattering in a different direction.

Photoelectric Effect

The complete absorption of an x-ray photon by an inner-shell electron, causing ionization.

Coherent Scatter

An interaction where a low-energy x-ray photon changes direction without a loss of energy.

X-Ray Tube

The component of the x-ray machine where x-rays are produced and converted from electrons. (heart of the generating system)

Collimator

A device that restricts the size of the x-ray beam as it exits the tubehead.

absorption

refers to the total transfer of energy from the x-ray photon to the atoms of matter through which the x-ray beam passes.