Alfred Otto Carl Nier

(1911)
University of Minnesota

Notable Achievements:

• Measured the isotopic composition of numerous elements including the discovery of four new isotopes.
• The development of the uranium-thorium-lead geochronological technique, and the determination of the half-lives of 235U and 238U.
• Accurate determination of the age of terrestrial samples by the uranium-thorium-lead method, which enabled a realistic age of the Earth to be calculated for the first time.
• Demonstrated that carbon isotopes varied in nature, thus disproving the notion that atomic weights are invariant in nature.
• The isotope separation of the carbon isotopes, and the application of these enriched isotopes to biological and medical research.
• The separation of the isotopes of 235U and 238U to confirm that 235U was the fissionable isotope of uranium.
• The design and development of the 60 º sector field mass spectrometer.
• The development of the helium leak detector.
• The use of multiple sector field mass spectrometers at the Oak Ridge Isotope Separation Plant to measure uranium enrichment throughout the Plant, using this as the basis of control engineering management of the Plant.
• The development of the potassium-argon geochronological technique.
• The measurement of variations of “well gas” 3He/4He isotope ratios, as compared to atmospheric values.
• The determination of the Absolute isotopic composition of a number of elements using enriched argon isotopes to calibrate a sector field mass spectrometer.
• His role in amalgamating the chemical and physical atomic weights scales into a unified system.
• The measurement of the isotopic composition of the noble gases in iron meteorites produced by cosmic ray bombardment.
• The use of electronics to revolutionize the mass doublet method of determining relative atomic masses, effectively turning mass spectrographs into mass spectrometers.
• The accurate measurement of the relative atomic masses of many elements using the Nier-Johnson double focusing mass spectrometer.
• The design of miniturarised mass spectrometers which were mounted in rockets and satellites to investigate the composition of the atmospheres of Earth, Mars and Venus.
• The investigation of the iaotopic composition of noble gases in Interplanetary Dust Particles.

Biographical Sketch

• Born May 28th, 1911.
• Received Bachelor of Electrical Engineering degree, The University of Minnesota, 1931.
• Received Ph. D. in Physics from the University of Minnesota in 1935.
• Post Doctoral Fellowship at Harvard University in 1936.
• Appointed to the staff of the Physics Department at the University of Minnesota in 1938.
• Appointed as a Regents’ Professor of Physics in 1966.
• Appointed as an Emeritus Professor of Physics at the University of Minnesota in 1980.

Academic Appointments

• Post Doctoral Fellowship at Harvard University , 1936-1938.
• Assistant Professor of Physics at the University of Minnesota, 1938.
• Research scientist at the Kellex Corporation, New York, 1943-1945.
• Regents’ Professor of Physics at the University of Minnesota, 1966.
• Emeritus Professor of Physics, University of Minnesota, 1980.
• Team member of the NASA Viking Expedition to Mars.
• Team member of the NASA mission to Venus.

Honors

• Honorary Doctor of Science, University of Minnesota, 1980.
• Arthur L. Day Medal of the Geological Society of America.
• William Bowie Medal of the American Geophysical Union.
• Victor Goldschmidt Medal of the Geochemical Society.
• The Field and Franklin Award of the American Chemical Society.
• Fellow of the National Academy of Science.
• Fellow of the American Philosophical Society.
• Fellow of the American Academy of Arts and Sciences.
• Foreign Member of the Max-Planck Institute for Chemistry in Germany.
• Foreign Member of the Royal Swedish Academy of Science.
• Medal of the Atomic Energy Commission.
• Medal of the National Aeronautics and Space Administration.
• The AOC Nier Symposium in Inorganic Mass Spectrometry was established by the Los Alamos, National Laboratory in his honour.

     Professor Nier was the author or coauthor of 216 papers published in the international scientific literature from 1935 to 1994. He made major contributions to the fields of atomic weights, geochronology, isotope geochemistry, meteoritics, noble gas geochemistry, nuclear physics and space science.