Updating international nuclear law
Radiation is energy in the process of being transmitted.
It may take such forms as light, or tiny particles much too small to see.
Gamma activity in a substance ( rock) can be measured with a scintillometer or Geiger counter.
X-rays are also electromagnetic waves and ionizing, virtually identical to gamma rays, but not nuclear in origin.
Many scientists then undertook study of these, and especially their medical applications.
This led to the identification of different kinds of radiation from the decay of atomic nuclei, and understanding of the nature of the atom.
Visible light, the ultra-violet light we receive from the sun, and transmission signals for TV and radio communications are all forms of radiation that are common in our daily lives.
All of us receive about 0.5-1 m Sv per year of gamma radiation from rocks, and in some places, much more.
They are more penetrating than alpha particles, but easily shielded – the most energetic of them can be stopped by a few millimetres of wood or aluminium.
They can penetrate a little way into human flesh but are generally less dangerous to people than gamma radiation.
Exposure produces an effect like sunburn, but which is slower to heal.
The weakest of them, such as from tritium, are stopped by skin or cellophane.Radiation particularly associated with nuclear medicine and the use of nuclear energy, along with X-rays, is 'ionizing' radiation, which means that the radiation has sufficient energy to interact with matter, especially the human body, and produce ions, it can eject an electron from an atom.