A 1927 chemistry graduate of the University of California at Berkeley, from which he received his doctorate in 1933, he studied radioactive elements and developed sensitive Geiger counters to measure weak natural and artificial radioactivity.
During World War II he worked in the Manhattan Project's Substitute Alloy Materials (SAM) Laboratories at Columbia University, developing the gaseous diffusion process for uranium enrichment.
After the war, Libby accepted professorship at the University of Chicago's Institute for Nuclear Studies, where he developed the technique for dating organic compounds using carbon-14.
He also discovered that tritium similarly could be used for dating water, and therefore wine.
Building on Ruben's and Kamen's discovery, Willard Libby and colleagues developed radiocarbon dating in 1949.
Martin Kamen died on August 31, 2002 in in Montecito, CA.
After a creature's death the isotope would slowly decay away over millennia at a fixed rate.
Thus the less of it that remained in an object, in proportion to normal carbon, the older the object was.
He sided with Edward Teller on pursuing a crash program to develop the hydrogen bomb, participated in the Atoms for Peace program, and defended the administration's atmospheric nuclear testing.
Libby resigned from the AEC in 1959 to become Professor of Chemistry at University of California, Los Angeles (UCLA), a position he held until his retirement in 1976.