Biographical Memoirs Volume 74 (1998) / Chapter Skim
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Alfred Otto Carl Nier
Alfred Otto Carl Nier
Pages 244-265
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Nier, regents professor emeritus at the University of Minnesota, user! mass spectrometers of his own design en c!
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Erikson, who recognized Al's talent early on, as clic! another mentor, Professor Henry Hartig of electrical · ~ engineering.
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Many of Tate's students studied ionization potentials of atoms and molecules and cross sections for ionization of molecules subjected to electron impact. The required analysis of the resulting fragment ions led naturally to the development of mass spectrometers in Tate's laboratory.
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His accurate measurements of the isotopic ratio 235U/238U bore on the uranium-lead method of dating of minerals where the ratio was of direct importance en c! inclirectly so because it afforclec!
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methods for ciating rocks en c! minerals, builcling a thermal diffusion column for the separation of carbon isotopes, thereby establishing collaborations with scientists who couIcI, with him, ~ 2 ~ , ~ , ~ ~ · ~ · ~ use 1~(; tracers to ~nveshgate a host of biochemical processes, further studies in neon en c!
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In the early development of large-scale separation of uranium isotopes, his laboratory was uniquely able to measure uranium isotopes, and he and a few students like Mark Inghram and Edward Ney were impressed into the task. Eight of the Nier instruments were later dispatched to other sites.
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to the Manhattan Project. Along with the analytical instruments, Al clesignec!
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by cryogenic techniques involving liquid helium. The cryogenic papers resultec!
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A totally different helium investigation arose in Al's laboratory from the discovery elsewhere that iron meteorites contain highly isotopically anomalous helium as the result of spalIation reactions inclucec! in the iron by cosmic ray particles en c!
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~, ~ about design, the first double-focussing instrument used a 6-tn.-radius magnetic sector similar to those employed in his successful isotope mass spectrometers. The success of the first instrument led to other improved designs and finally to an instrument about 2.5 times larger than the original.
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to I Mattauch in 1956 that the chemical atomic weight scale baser!
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much of his efforts in space physics to overcoming the problem that chemically active species, such as atomic oxygen and nitrogen, although present in the upper atmospheres of planets in concentrations that are important to know, interact quickly with surfaces of the instruments for their detection. He macle the valuable discovery that in his open-source mass spectrometer, where the Nier ion source is exposer!
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isotopic abundances of the noble gases in one such meteorite with values fount! by Nier in the Martian atmosphere.
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This highly complex instrument, which incluclec! mass spectrometer detection, conic!
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A refiner! laboratory version of this spectrometer was the perfect vehicle for Al's late work with a giftec!
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The relationship between Al and "Buddy" Thorness was very fruitful and very deep. The respect and consideration that Al had for the "shop" and the skilled and dedicated individuals who worked there was a symbol of the fruitful old system in which experimental physics was greatly advanced by dedicated staff and universities provided facilities as a matter of course.
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Day Mecial of the Geological Society of America, William Bowie Mecial of the American Geophysical Union, Victor Goicischmicit Mecial of the Geochemistry Society, en c! the Fielc!
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REFERENCES Alfred Otto Carl Nier, American physicist. In Modern Scientists and Engineers, pp.
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52:933-37. 1939 The isotopic constitution of uranium and the half-lives of the uranium isotopes.
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The distribution of cosmic-ray produced rare gases in iron meteorites.
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Venus thermosphere: In situ composition measurements, the temperature profile, and the homopause altitude. Science 203:768-69.
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