Alpha particle types: eventually named alpha, beta, and gamma by Rutherford, based on penetration of objects and deflection by a magnetic field. Alpha rays were defined by Rutherford as those having the lowest penetration of ordinary objects. Rutherford's work also included measurements of the ratio of an alpha particle's mass to its charge, which led him to the hypothesis that alpha particles were doubly charged helium ions (later shown to be bare helium nuclei). In 1907, Ernest Rutherford and Thomas Royds finally proved that alpha particles were indeed helium ions. To do this they allowed alpha particles to penetrate a very thin
Americium-241 starting material for the production of other transuranic elements and transactinides – for example, neutron bombardment of Am yields Am: formula_3 From there, 82.7% of Am decays to Cm and 17.3% to Pu: 82.7% → formula_10 17.3%→ formula_11 In the nuclear reactor, Am is also up-converted by neutron capture to Am and Am, which transforms by β-decay to Cm: Irradiation of Am by C or Ne ions yields the isotopes Es (einsteinium) or Db (dubnium), respectively. Furthermore, the element berkelium (Bk isotope) had been first intentionally produced and identified by bombarding Am with alpha particles, in 1949, by the same