Types of Radiation
Alpha Radiation
Alpha radiation is heavy, very short-range and is an ejected nuclei . Characteristics of alpha radiation are:
- Does not penetrate human skin or clothing and is not an external hazard
- Can be harmful to humans if the materials are inhaled, swallowed, or absorbed through open wounds.
- Thin-window Geiger-Mueller (GM) probe can detect the presence of alpha radiation.
- Cannot be detected through layers of water, dust, paper, or other material.
- Travels only a short distance (a few cm) in air.
- May travel a few metres in air and is moderately penetrating.
- Beta radiation can penetrate human skin and prolonged exposure may cause skin injury.
- Beta-emitting can be very harmful to humans if the materials are inhaled, swallowed, or absorbed through open wounds.
- Can be detected with a thin-window GM probe, some beta emitters are very low-energy and are difficult to detect
- Clothing provides moderate protection against beta radiation.
- Able to travel several metres in air and many centre metres in human tissue and are sometimes called "penetrating" radiation
- Sealed radioactive sources and machines that emit this radiation are an external hazard to humans.
- These electromagnetic radiations differ to light and radio waves only in the amount of energy they have.
- Dense materials are needed for shielding, clothing provides little shielding but can prevent contamination of the skin by gamma-emitting materials.
- Detected by GM probe and survey meters with a Scintillators such as sodium iodide.
- Gamma radiation and/or characteristic x rays often accompany the emission of alpha and beta radiation during radioactive decay
- Able to travel several metres through most materials
- Sources and machines that emit this radiation are extremely hazard to humans.
- Sometimes considered a more severe hazard due to neutron activation, the ability of neutron radiation to induce radioactivity in most substances it encounters
- Dense materials are needed for shielding
- Most commonly detected by with a Scintillators and other specialised equipment.
- Neutrons also degrade materials; intense bombardment with neutrons creates dislocations in the materials, leading to embrittlement of metals and other materials.
Examples of some alpha emitters: americium 241, radium, radon, uranium, thorium.
Beta Radiation
Beta radiation is a light, short-range and is an ejected electron. Characteristics of beta radiation are:
Examples of some pure beta emitters: strontium-90, carbon-14, tritium, and sulfur-35.
Gamma and X Radiation
Gamma radiation and x rays are highly penetrating electromagnetic radiation. Characteristics of this radiation are:
Neutron Radiation
Neutrons may be emitted during either spontaneous or induced nuclear fission, nuclear fusion processes, very high energy reactions such as in the accelerator-based neutron sources and in cosmic ray interactions.
