Alpha decay helium produced on Earth is the result of the alpha decay of underground deposits of minerals containing uranium or thorium. The helium is brought to the surface as a by-product of natural gas production. Alpha particles were first described in the investigations of radioactivity by Ernest Rutherford in 1899, and by 1907 they were identified as He ions. By 1928, George Gamow had solved the theory of alpha decay via tunneling. The alpha particle is trapped in a potential well by the nucleus. Classically, it is forbidden to escape, but according to the (then) newly discovered principles of quantum mechanics,
Mendelevium produced by bombarding plutonium and americium targets with lighter ions of carbon and nitrogen. The most important and most stable isotopes are in the range from Md to Md and are produced through bombardment of einsteinium isotopes with alpha particles: einsteinium-253, -254, and -255 can all be used. Md is produced as a daughter of No, and Md can be produced in a transfer reaction between einsteinium-254 and oxygen-18. Typically, the most commonly used isotope Md is produced by bombarding either einsteinium-253 or -254 with alpha particles: einsteinium-254 is preferred when available because it has a longer half-life and therefore