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Antoine Henri Becquerel
Conducts experiments that led to the discovery of radioactivity. -
j.j. Thomson
Of Britain discovers the electron while studying the cathode rays. -
Frederick Soddy
Observes spontaneous denigration of radioactive elements into variants, became known as isotopes. -
Rutherford and Soddy
Publish their theory of radioactive decay. -
Rutherford and Thomson
Rutherford discovers that alpha rays are heavy and positive particles. Thomson proposes the "plum-pudding" model of the atom. -
Albert Einstein
Publishes the special theory of relativity regarding convertibility of matter and energy. E=mc2 -
Rutherford
Conducts experiments that help discover the nucleus of the atom and disproving the 'plum-pudding' theory. -
Frederick Proescher
Published first study on the injection of radium for therapy of various diseases. -
Rutherford
Bombard nitrogen gas with alpha particles and obtains atoms of an oxygen isotope and protons, being the first artificially induced nuclear reaction. -
First radiotracer studies in animals
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James Chadwick
Discovers neutrons. -
Atomic Bomb idea
Concept of nuclear chain reaction discovered and idea of the atomic bomb was invented. -
Frederic and Irene Joliot
Discover artificial radioactivity.
Enrico Fermi irridates uranium with neutrons and unknowingly achieve the first nuclear fission. -
Fermi
Published his theory of mesons which explained the interaction between protons and neutrons, new field theory of nuclear forces -
John H. Lawrence
Made the first clinical therapeutic application of an artificial radionuclide. -
Roosevelt
President launches the Manhattan Project, a project for the secret creation of the atomic bomb. -
Fermi
Produces first controlled and sustained nuclear fission reaction -
Atomic Bomb
The United States explodes its first atomic bomb and drops the bomb, Little Boy, a uranium bomb, on Hirsoshima. -
Abbot Laboratories
began distribution of radioisotopes. -
Soviet Union
Achieves its first nuclear chain reaction and detonates its first atomic bomb. -
David Kuhl
Invented a photoreading system for radionuclide scanning.