Arnold, James, 1923-2012

Chemist and planetary scientist.

Biography

James Richard Arnold (b.1923- ), professor and chemist, received his bachelor degree, masters, and Ph.D degrees at Princeton University in 1943, 1945 and 1946 respectively. While doing graduate work, Arnold was associated with the Manhattan Project for the years 1943-1945. After completing his Ph.D., he joined the newly formed Institute for Nuclear Studies at the University of Chicago as a postdoctoral fellow, and in 1947, he went to Harvard University as a National Research Fellow.

The following year, Arnold returned to the Institute for Nuclear Studies in Chicago, first as a research associate working with W.F. Libby on the development of radiocarbon dating (until 1950), then as an assistant professor of chemistry. Arnold then developed, simultaneously with a group at Los Alamos, the liquid scintillation spectrometer for carbon-14 and tritium, the latter a radioactive isotope of hydrogen. He also discovered the short-lived isotope Be-7 in nature, which has found applications in meteorological research.

From 1955 to 1958, Arnold was on the chemistry faculty at Princeton University. While there he discovered the long-lived isotope Be-10 in nature and began the study of its distribution in the natural enviroment. In 1958, he came to UCSD as one of the first appointments in what became the main campus. Soon thereafter he became the founding chairman of the chemistry department and a full professor.

In the 1960s, Arnold primarily studied cosmic-ray products in meteorites and lunar samples. With several colleagues he demonstrated the approximate constancy of the cosmic-ray flux over periods up to millions of years.

Beginning in the same period and throughout his UCSD career he also participated in NASA planetary missions. He was the Principal Investigator for the Gamma Ray Spectrometer experiment first on the unmanned Ranger 3, 4, and 5 missions and then on the Apollo 15 and 16 manned missions to the moon. He was a Co-investigator on a similar experiment on the failed Mars Observer mission.

Arnold is a consultant to NASA and has served as associate editor of the Journal of Chemical Physics . He was chairman of the sub-committee on radiochemistry of the National Research Council, and, in 1966-1968, he served on the International Technical Cooperation and Assistance Panel of the President's Science Advisory Committee. In 1964, he was elected to the National Academy of Sciences and has served on several of their committees. He received the E.O. Lawrence Award from the Atomic Energy Commission in 1968, and, in 1970, Arnold was honored by NASA with its medal for "Exceptional Scientific Achievement" in recognition of his work on lunar samples assigned to him by NASA. In 1976, he received the Leonard Medal from the Meteoritical Society. From 1979 to 1989, he served as director of the UCSD's newly established California Space Institute, a statewide research organization with emphasis on the useful applications of space. From 1983-1993, he occupied the Harold Urey Chair of Chemistry.