Information in everyday life via International Atomic Energy Agency (IAEA)
What is half-life in the terms of radiation? It is the time taken for half the radionuclides to disintegrate or decay. This differs for each and every radioelement, ranging from fractions of a second to billions of years.
What is half-life in the terms of radiation? It is the time taken for half the radionuclides to disintegrate or decay. This differs for each and every radioelement, ranging from fractions of a second to billions of years.
There are different types of radiations, mainly:
- Alpha radiation is emitted by atoms such as Uranium & Radium, which contains heavy, positively charged particles.
- Beta radiation contains electrons.
- Gamma rays are electromagnetic radiation, which are similar to X-rays, light, and radio waves.
- Neutrons interacts with atoms to form alpha, beta, gamma, or X-rays.
Sievert (Sv) is the unit of absorbed radiation dose*. One sievert (Sv) is a large quantity hence, radiation doses normally encountered are expressed in millisievert (mSv) or microsievert (µSv), which are one-thousandth or one millionth of a sievert. For example, one chest X-ray will give about 0.2 mSv of radiation dose.
Useful information via International Atomic Energy Agency (IAEA)
The occupational exposure of any worker shall be so controlled that the following
limits not exceed:
(a) an effective dose* of 20 mSv per year, averaged over five consecutive years
(b) an effective dose* of 50 mSv in any single year
(c) an equivalent dose* to the lens of the eye of 150 mSv in a year
(d) an equivalent dose* to the extremities (hands and feet) or the skin of 500 mSv in a year.
Useful information via National Environment Agency (NEA)
For members of the public, the effective dose* limit to the whole body is 1 mSv per year.
For radiation workers, the limit on the effective dose* to the whole body is 20 mSv a year, averaged over five years, and that the effective dose* should not exceed 50 mSv in any one year.
The equivalent dose* limit of a pregnant worker to the surface of the woman’s abdomen shall be 2 mSv for the rest of the pregnancy.
For a radiation source in a walled enclosure or a cabinet, the radiation level anywhere outside the walled enclosure or cabinet, accessible to anyone, should not be more than 10 µSv/hr.
The radiation levels must not exceed 0.5 µSv/hr, outside the defined area where the radioactive materials are stored.
*Information via radiologyinfo.org
- Absorbed dose is used to assess the potential for biochemical changes in specific tissues.
- Equivalent dose is used to assess how much biological damage is expected from the absorbed dose. (Different types of radiation have different damaging properties.)
- Effective dose is used to assess the potential for long-term effects that might occur in the future.