31st Dec '25

Properties of Radiation

When radiation from radioactive materials with neutral atoms or molecules these may become (charged). When radiation ionises molecules in living cells it can cause damage, including .

The larger the dose of radiation the greater the risk of cancer. As radiation passes through a material it can be absorbed. The greater the thickness of a material the greater the absorption:

alpha (α) radiation, easily absorbed by of air or a thin sheet of paper;
beta (β) radiation, easily passes through air or paper but is mostly absorbed by of metal;
gamma (γ) radiation, is very penetrating and requires of lead or metres of concrete to absorb most of it.

When sources of radiation are inside the body:

alpha radiation is the most dangerous because it is so strongly absorbed by cells;
beta and gamma radiation are less dangerous because cells are less likely to absorb the radiation.

When sources of radiation are outside the body:

beta and gamma radiation are the most dangerous because they can reach the cells of organs and may be absorbed by them;
alpha radiation is least dangerous because it is unlikely to reach living cells.