Alfred Otto Carl Nier (May 28, 1911 – May 16, 1994) was an American

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

who pioneered the development of mass spectrometry. He was the first to use mass spectrometry to isolate

uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exi ...

which was used to demonstrate that ²³⁵U could undergo fission and developed the

sector mass spectrometer A sector instrument is a general term for a class of mass spectrometer that uses a static electric (E) or magnetic (B) sector or some combination of the two (separately in space) as a mass analyzer. Popular combinations of these sectors have been ...

configuration now known as Nier-Johnson geometry.

Early life and education

He was born in St. Paul, Minnesota on May 28, 1911. Nier showed an early ability in mathematics and

science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...

, coupled with an aptitude for craft and mechanical work. Nier's

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

immigrant parents had little education or financial resources but their determination for his development meant that he was able to attend the nearby

University of Minnesota The University of Minnesota, formally the University of Minnesota, Twin Cities, (UMN Twin Cities, the U of M, or Minnesota) is a public land-grant research university in the Twin Cities of Minneapolis and Saint Paul, Minnesota, United States. ...

. Though he graduated in electrical engineering in 1931, the lack of engineering jobs during the Great Depression encouraged him to take up graduate study in

physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...

Career

Harvard

In 1936, his spectroscopic skills won him a fellowship and substantial grant at

Harvard University Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of high ...

. His work there led to the 1938 publication of measurements of the relative abundance of the

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...

s of

uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

, measurements that were used by

Fritz Houtermans Friedrich Georg "Fritz" Houtermans (January 22, 1903 – March 1, 1966) was a Dutch-Austrian-German atomic and nuclear physicist and Communist born in Zoppot near Danzig, West Prussia to a Dutch father, who was a wealthy banker. He was brought up ...

and

Arthur Holmes Arthur Holmes (14 January 1890 – 20 September 1965) was an English geologist who made two major contributions to the understanding of geology. He pioneered the use of radiometric dating of minerals, and was the first earth scientist to grasp ...

in the 1940s to estimate the age of the

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

The Manhattan Project

Nier returned to Minnesota in 1938 to be near his ageing parents. In 1940, on the request of Enrico Fermi, he and a few students, including Edward Ney, prepared a pure sample of

using an early mass spectrograph designed by Nier, for John R. Dunning's team at

Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...

. On the day of its receipt (it was sent by US Postal Mail), Dunning's team was able to demonstrate that uranium-235 was the

responsible for nuclear fission, rather than the more abundant uranium-238. Confirmation of this suspected fact was a critical step in the development of the atomic bomb. From 1943 to 1945, Nier worked with

Kellex Corporation The Kellex Corporation was a wholly owned subsidiary of M. W. Kellogg Company. Kellex was formed in 1942 so that Kellogg's operations relating to the Manhattan Project could be kept separate and secret. "Kell" stood for "Kellogg" and "X" for sec ...

in Manhattan, New York City on the design and development of efficient and effective mass spectrographs for use in the

Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...

to build the atomic bomb in

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. During the war most of the spectrographs used for monitoring uranium separations were designed by Nier.

Later work

After the war, he returned to Minnesota where he worked on

geochronology Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is ...

, the upper atmosphere, space science and

noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low ch ...

es. Nier designed the miniature mass spectrometers used by the Viking Landers to sample the atmosphere of Mars.

Death

Active to the end of his life, he died on May 16, 1994, two weeks after being

paralysed Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...

in a motor accident.

Honors

Nier was a member, National Academy of Sciences; and a foreign scientific member of the Max Planck Society. The Martian crater Nier and the mineral nierite (tiny

silicon nitride Silicon nitride is a chemical compound of the elements silicon and nitrogen. is the most thermodynamically stable and commercially important of the silicon nitrides, and the term "silicon nitride" commonly refers to this specific composition. It ...

inclusions in meteorites) were named after him. The Nier Prize is awarded annually by the

Meteoritical Society The Meteoritical Society is a non-profit scholarly organization founded in 1933 to promote research and education in planetary science with emphasis on studies of meteorites and other extraterrestrial materials that further our understanding of the ...

and recognizes outstanding research in meteoritics and closely allied fields by young scientists.

References

External links

1965 Audio Interview with Alfred Nier by Stephane Groueff
Voices of the Manhattan Project
Annotated Bibliography for Alfred O.C. Nier from the Alsos Digital Library for Nuclear Issues
* * * * * {{DEFAULTSORT:Nier, Alfred O. C. 1911 births 1994 deaths University of Minnesota College of Science and Engineering alumni Harvard Fellows Nier, Alfred, O. C. 20th-century American physicists Mass spectrometrists Fellows of the American Physical Society Members of the United States National Academy of Sciences Thomson Medal recipients Members of the Royal Swedish Academy of Sciences Recipients of the V. M. Goldschmidt Award