Not all atoms are stable.
Unstable atoms seek to become stable by changing the structure of their nucleus, and emitting surplus energy as radiation.
This process is called Radioactivity and atom is said to be radioactive.
The radiation emitted by a stabilizing atom is strong enough to displace an electron from another atom when it comes into contact with it.
The removal of the electron causes the atom to become an ion .
This process is known as ionization .
Ionization is the aspect of radiation that can cause:
1. An electronic signal for detectors – allowing you to detect and measure radiation.
2. Biological damage to tissue – this is one reason why radiation can be hazardous to the human body.
Radiation is classified as ionizing and non-ionizing. Ionizing radiation consists of swift atomic, subatomic particles and photons having the energy enough to produce significant ionization of a substance (Alpha, beta, neutrons).
Non-ionizing radiation is any kind of radiation in the electromagnetic spectrum that does not have enough energy to remove an electron from an atom and turn it into an ion.
Ionizing radiation is radiation with enough energy so that during an interaction with an atom, it can remove tightly bound electrons from the orbit of an atom, causing the atom to become charged or ionized. I onizing radiation occurs in two forms - waves or particles
To reduce external exposure as much as possible:
The "Golden Rules" for reducing external radiation exposure (from sources outside the body) are the use of Shielding, Distance and Time :
SHIELD the source as much as possible (type and thickness of shielding required will depend on the energy and type of radioactive emissions). Keep TIME spent near source as short as possible (dose is proportional to exposure time). Maintain as large a DISTANCE from source as possible (dose falls off rapidly, following the inverse square law).