Alpha particle introduction
Alpha particles are positively charged high-energy particles (He-4 atomic nuclei) that rapidly lose energy after passing through the medium. They are usually produced when some heavy atoms (eg uranium, radium) or some artificial nuclides decay. Alpha particles run in the medium and quickly lose energy and cannot penetrate far. However, it can cause damage to the tissue even if it cannot penetrate deeply. Alpha particles are usually completely absorbed by human outer necrotic skin, and radioisotopes released by alpha particles do not pose a danger outside the human body. However, once they are inhaled or injected, it can be very dangerous. Alpha particles can be blocked by a piece of tissue paper.