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Lise Meitner was an Austrian-Swedish physicist who was one of those responsible for the discovery of the element protactinium and nuclear fission. While working on radioactivity at the Kaiser Wilhelm Institute of Chemistry in Berlin, she discovered the radioactive isotope protactinium-231 in 1917. In 1938, Meitner and her nephew, the physicist Otto Robert Frisch, discovered nuclear fission. She was praised by Albert Einstein as the "German Marie Curie".
The transuranium elements are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of them are radioactively unstable and decay into other elements. With the exception of neptunium and plutonium which have been found in trace amounts in nature, none occur naturally on Earth and they are synthetic.
Ernest Orlando Lawrence was an American nuclear physicist and winner of the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation for the Manhattan Project, as well as for founding the Lawrence Berkeley National Laboratory and the Lawrence Livermore National Laboratory.
Otto Hahn was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner discovered radioactive isotopes of radium, thorium, protactinium and uranium. He also discovered the phenomena of atomic recoil and nuclear isomerism, and pioneered rubidium–strontium dating. In 1938, Hahn, Lise Meitner and Fritz Strassmann discovered nuclear fission, for which Hahn received the 1944 Nobel Prize for Chemistry. Nuclear fission was the basis for nuclear reactors and nuclear weapons.
Edwin Mattison McMillan was an American physicist credited with being the first to produce a transuranium element, neptunium. For this, he shared the 1951 Nobel Prize in Chemistry with Glenn Seaborg.
Sir James Chadwick, was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspired the U.S. government to begin serious atom bomb research efforts. He was the head of the British team that worked on the Manhattan Project during World War II. He was knighted in Britain in 1945 for his achievements in physics.
Willard Frank Libby was an American physical chemist noted for his role in the 1949 development of radiocarbon dating, a process which revolutionized archaeology and palaeontology. For his contributions to the team that developed this process, Libby was awarded the Nobel Prize in Chemistry in 1960.
Emilio Gino Segrè was an Italian and naturalized-American physicist and Nobel laureate, who discovered the elements technetium and astatine, and the antiproton, a subatomic antiparticle, for which he was awarded the Nobel Prize in Physics in 1959 along with Owen Chamberlain.
The year 1939 in science and technology involved some significant events, listed below.
Otto Robert Frisch was an Austrian-born British physicist who worked on nuclear physics. With Otto Stern and Immanuel Estermann he first measured the magnetic moment of the proton. With Lise Meitner he advanced the first theoretical explanation of nuclear fission and first experimentally detected the fission by-products. Later, with his collaborator Rudolf Peierls he designed the first theoretical mechanism for the detonation of an atomic bomb in 1940.
The Frisch–Peierls memorandum was the first technical exposition of a practical nuclear weapon. It was written by expatriate German-Jewish physicists Otto Frisch and Rudolf Peierls in March 1940 while they were both working for Mark Oliphant at the University of Birmingham in Britain during World War II.
The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram from Danish physicist Niels Bohr referring to his housekeeper, Maud Ray.
The S-1 Executive Committee laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain.
Francis Goddard Slack was an American physicist. He was a physics teacher, researcher, and administrator in academia who was renowned for placing equal emphasis on teaching and on research.
G. Norris Glasoe was an American nuclear physicist. He was a member of the Columbia University team which was the first in the United States to verify the European discovery of the nuclear fission of uranium via neutron bombardment. During World War II, he worked at the MIT Radiation Laboratory. He was a physicist and administrator at the Brookhaven National Laboratory.
Eugene Theodore Booth, Jr. was an American nuclear physicist. He was a member of the historic Columbia University team which made the first demonstration of nuclear fission in the United States. During the Manhattan Project, he worked on gaseous diffusion for isotope separation. He was the director of the design, construction, and operation project for the 385-Mev synchrocyclotron at the Nevis Laboratories, the scientific director of the SCALANT Research Center, and dean of graduate studies at Stevens Institute of Technology. Booth was the scientific director of the SCALANT Research Center, in Italy.
The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics in the first half of the 20th century. Early in the century, Ernest Rutherford developed a crude model of the atom, based on the gold foil experiment of Hans Geiger and Ernest Marsden. In this model, atoms had their mass and positive electric charge concentrated in a very small nucleus. By 1920, isotopes of chemical elements had been discovered, the atomic masses had been determined to be (approximately) integer multiples of the mass of the hydrogen atom, and the atomic number had been identified as the charge on the nucleus. Throughout the 1920s, the nucleus was viewed as composed of combinations of protons and electrons, the two elementary particles known at the time, but that model presented several experimental and theoretical contradictions.
Nuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or more smaller, lighter nuclei and often other particles. The fission process often produces gamma rays and releases a very large amount of energy, even by the energetic standards of radioactive decay. Scientists already knew about alpha decay and beta decay, but fission assumed great importance because the discovery that a nuclear chain reaction was possible led to the development of nuclear power and nuclear weapons. Hahn was awarded the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission.
Christopher Hollis Johnson CBE was a British chemist and physicist. He worked in weapons research and was part of the technical committee of Tube Alloys, the UK's secret atomic weapon development programme.
References
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- ↑ Auto Editors of Consumer Guide. "1906-1939 Jeep: Jeep Makes History". HowStuffWorks. Archived from the original on 2012-05-01. Retrieved 2012-05-31.