Penetration properties of radiations

• Alpha particles are absorbed by just a few millimetres of air or by a thin sheet of paper.
• Beta particles can pass through air and paper but are completely absorbed by a sheet of metal just a few millimetres thick.
• Gamma rays pass through most materials easily but are absorbed by a thick sheet of lead or by several metres of concrete.
• Radiation dose is measured using units such as sieverts (Sv) and millisieverts (mSv).