Drawing done by J. Gunn (1932) of the New Zealand born physicist Sir Ernest Rutherford (1871-1937), considered to be the father of nuclear physics. He identified three types of ionising radiations produced by radioactive decay which he called alpha, beta and gamma rays. He later proved that alpha rays were helium atoms deprived of two electrons. In 1911 he elaborated an atomic model in which the positive charge of the atom (protons) was concentrated in a very small region, the nucleus. He also showed that the structure of an atom could be changed (nuclear transmutation) by bombarding it with alpha particles. In 1908 he was awarded the Nobel Prize for chemistry. Kept at the National Portrait Gallery