Functional basic of ionising radiation depends on –
Ionizing radiation gives energy to an electron which results in excitation of electron and if radiation carries enough energy there is ejection of an electron from the atom, leaving its parent atom positively charged.
Excitation:- Elevation of an electron to a higher energy level without actual ejection of the electron. It occurs when radiation excites an electron from an occupied orbit into a higher energy orbit.
Ionization:- There is an actual ejection of electrons from atom. an It occurs when radiation carries enough energy to completely remove an electron from an atom.
Pyramidine base pairing
Removal of orbital electron
Linear energy transfer
Adding orbital electron