Ralph Arthur James (23 September 1920 in

Salt Lake City Salt Lake City, often shortened to Salt Lake or SLC, is the capital and most populous city of the U.S. state of Utah. It is the county seat of Salt Lake County, the most populous county in the state. The city is the core of the Salt Lake Ci ...

, Utah – 24 February 1973 in

Alamo The Battle of the Alamo (February 23 – March 6, 1836) was a pivotal event and military engagement in the Texas Revolution. Following a 13-day siege, Mexican troops under President General Antonio López de Santa Anna reclaimed the Alam ...

, California) was an American chemist at the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

who co-discovered the elements

curium Curium is a synthetic chemical element; it has symbol Cm and atomic number 96. This transuranic actinide element was named after eminent scientists Marie and Pierre Curie, both known for their research on radioactivity. Curium was first inten ...

(1944) and

americium Americium is a synthetic element, synthetic chemical element; it has Chemical symbol, symbol Am and atomic number 95. It is radioactive and a transuranic member of the actinide series in the periodic table, located under the lanthanide element e ...

(1944–1945). Later he worked at

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school then known as the southern branch of the C ...

and for the Lawrence Livermore laboratory in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. He also worked on

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

and nuclear

spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...

Scientific career

James was part of the Laboratory of Metallurgy, University of Chicago, the team directed by

Glenn T. Seaborg Glenn Theodore Seaborg ( ; April 19, 1912February 25, 1999) was an American chemist whose involvement in the synthesis, discovery and investigation of ten transuranium elements earned him a share of the 1951 Nobel Prize in Chemistry. His work i ...

. The laboratory had large amounts of

plutonium Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four ...

(discovered in 1940–41) that was being produced at the

Hanford Site The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. It has also been known as SiteW and the Hanford Nuclear R ...

to make

nuclear weapons A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either nuclear fission, fission (fission or atomic bomb) or a combination of fission and nuclear fusion, fusion reactions (thermonuclear weap ...

. This allowed them to discover two new elements, although the difficulties for study and isolation were great. In 1944, Seaborg decided to extend the search to heavier elements, and instructed James and Leon O. Morgan to send samples of irradiated plutonium to

Albert Ghiorso Albert Ghiorso (July 15, 1915 – December 26, 2010) was an American nuclear scientist and co-discoverer of a record 12 chemical elements on the periodic table. His research career spanned six decades, from the early 1940s to the late 1990s. Biog ...

for analysis. By identifying characteristics of emitted alpha particles they found the new elements.

Discovery of curium

Curium (atomic number 96) was discovered in 1944 by

, James and

during World War II in the Chicago Metallurgical Laboratory, as part of the

Manhattan Project The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the ...

, by bombarding

with

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

ions An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

. It was named in honor of

Pierre Curie Pierre Curie ( ; ; 15 May 1859 – 19 April 1906) was a French physicist, Radiochemistry, radiochemist, and a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. He shared the 1903 Nobel Prize in Physics with his wife, ...

and Marie Sklodowska Curie.

Discovery of americium

Similarly, americium (atomic number 95) was discovered in 1944–45 by

, James, Leon O. Morgan and

, working as part of the

. By bombarding plutonium

neutron The neutron is a subatomic particle, symbol or , that has no electric charge, and a mass slightly greater than that of a proton. The Discovery of the neutron, neutron was discovered by James Chadwick in 1932, leading to the discovery of nucle ...

s in the 60-inch

cyclotron A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: Januar ...

at the

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

. The element is named after America, especially the United States of America, and because it is a homologous element of

europium Europium is a chemical element; it has symbol Eu and atomic number 63. It is a silvery-white metal of the lanthanide series that reacts readily with air to form a dark oxide coating. Europium is the most chemically reactive, least dense, and soft ...

(atomic number 63), it is positioned right above it on periodic charts.

Honors

* Ralph James became a member of the Guggenheim Foundation in 1955, for chemistry.

Publications

* ''The New Element Curium (Atomic Number 96)''. Glenn T. Seaborg, Ralph A. James, & Albert Ghiorso. January 1948. * ''The New Element Americium (Atomic Number 95)''.] Glenn T. Seaborg, Ralph A. James, & Leon O.Morgan. NNES PPR (National Nuclear Energy Series, Plutonium Project Record), Vol. 14 B The Transuranium Elements: Research Papers, Paper No. 22.1, McGraw-Hill Book Co., Inc., New York, 1949. * ''L-Electron Capture and Alpha-Decay in Np235.'' Ralph A. James, Albert Ghiorso, Donald Orth. Radiation Laboratory, University of California, Berkeley. Phys. Rev. 85, 369 (1952). * ''Excitation Functions of Proton-Induced Reactions of Nb93.'' Ralph A. James. Physical Review – January 1954. Vol 93, Number 2, p. 288-290. * ''Proton Induced Reactions of Thorium—Fission Yield Curves.'' Howard A. Tewes and Ralph A. James. Department of Chemistry, University of California, Los Angeles. Phys. Rev. 88, 860 (1952). * ''Cross Sections for Nuclear Reactions Involving Nuclear Isomers.'' Bruno Linder* and Ralph A. James. Department of Chemistry, UCLA, California. Phys. Rev. 114, 322–325 (1959). * Isomeric States of Nd141 and Sm143. Ralph A. James and Carleton D. Bingham. Department of Chemistry, University of California, Los Angeles. Phys. Rev. 117, 810 (1960). * ''Estimate of radiation dose to thyroid of the Rongelap children following the Bravo event.'' Lawrence Radiation Laboratory, 1964. * ''Calculation of radioactive iodine concentrations in milk and human thyroid as a result of nuclear explosions.'' Ralph A. James. UCRL 7716. Nuclear Explosions - Peaceful Applications, UC-35. University of California, Lawrence Radiation Laboratory, 1964.

References

* Darleane C. Hoffman,

, and

. ''The Transuranium People: The Inside Story.'' London, England: Imperial College Press, 2000. Chapter 4 (pp. 100–129) * Aaron J. Ihde. ''The Development of Modern Chemistry.'' New York: Dover Publications, Inc., 1984. p. 749. * S. G. Thompson, A. Ghiorso, and G. T. Seaborg. ''The New Element Berkelium (Atomic Number 97).''

Physical Review ''Physical Review'' is a peer-reviewed scientific journal. The journal was established in 1893 by Edward Nichols. It publishes original research as well as scientific and literature reviews on all aspects of physics. It is published by the Ame ...

, vol. 80, num 5, 1950, pp. 781–789. doi:10.1103/PhysRev.80.781

External links

Fotografía de Ralph A. James en Brookfield Zoo, Chicago.
LBNL Image Library—Collection Berkeley-Lab/Seaborg-Archive. {{DEFAULTSORT:James, Ralph 20th-century American chemists 1920 births 1973 deaths University of Chicago faculty University of California, Los Angeles faculty Americium