Alpha Particles

-Alpha particles are helium nuclei
-They are made up of 2 protons and 2 neutrons
-They're big, heavy and slow moving
-They therefore don't penetrate far into materials but are stopped quickly
-Becuase of their size they bash into a lot of atoms and knock electrons off which creates lots of ions 
-Because they're electrically charged (with a positive charge) alpha particles are deflected by electric and magnetic fields