Any material “stopping” ionizing radiationAny radiation which directly or indirectly ionizes, e.g. alp.... Alpha radiationEnergy dispersion through matter or space. In atomic physics... can already be totally absorbed by a sheet of paper; beta radiationBeta radiation is the emission of electrons or positrons dur... is absorbed by a few centimetres of plastic material or 1 cm of aluminium. Materials with a high atomic numberNumber of protons in an atomic nucleus. Each chemical elemen... and high density are used for gamma radiationHighly-energetic, short-wave electromagnetic radiation emitt... absorbers (lead, steel, concrete, partially with special additions). NeutronUncharged elementary particle with a mass of 1.67492716 ·10... absorbers such as boron, hafniumMetal; neutron absorber which is mainly effective in the the... and cadmium are used in control rods for reactors.