Raymond Davis, Jr.

Raymond Davis, Jr. (October 14, 1914 – May 31, 2006) was an American chemist, physicist, and Nobel Prize in Physics laureate.

Additional recommended knowledge

What is the Correct Way to Check Repeatability in Balances?

Weighing the right way

Daily Sensitivity Test

Biography

Davis was born in Washington, D.C., where his father was a photographer for the National Bureau of Standards. He spent several years as a choir boy to please his mother, although he could not carry a tune. He enjoyed attending the concerts at the Watergate before air traffic was loud enough to drown out the music. His brother Warren, 14 months younger than he, was his constant companion in boyhood. He graduated in chemistry from the University of Maryland in 1938. He also received a masters degree from that school and a Ph.D. from Yale University in physical chemistry in 1942.

Most of the war years were spent at Dugway Proving Ground, Utah observing the results of chemical weapons tests and exploring the Great Salt Lake basin for evidences of its predecessor, Lake Bonneville.

Career

Upon his discharge from the army in 1946, Davis went to work at Monsanto Chemical Company's Mound Laboratory, in Miamisburg, Ohio, doing applied radiochemistry of interest to the United States Atomic Energy Commission. In 1948, he joined Brookhaven National Laboratory, which was dedicated to finding peaceful uses for atomic energy.

Davis reports that he was asked "to find something interesting to work on," and dedicated his career to the study of neutrinos, particles which had been predicted to explain the process of beta decay, but whose separate existence had not been confirmed. Davis investigated detecting neutrinos by inverse beta decay, the process by which a neutrino brings enough energy to a nucleus to make certain stable isotopes into radioactive ones. Since the rate for this process is very low, the number of radioactive atoms created in neutrino experiments is very small, and Davis began investigating the rates of processes other than inverse beta decay that would mimic the signal of neutrinos. Using barrels and tanks of carbon tetrachloride as detectors, Davis characterized the rate of the production of ³⁷Argon as a function of altitude and as a function of depth underground. He deployed a detector containing chlorine atoms at the Brookhaven Reactor in 1954 and later one of the reactors at Savannah River. These experiments failed to detect a surplus of radioactive argon when the reactors were operating over when the reactors were shut down, and this was taken as the first experimental evidence that neutrinos causing the chlorine reaction, and antineutrinos produced in reactors, were distinct. Detecting neutrinos proved considerably more difficult than not detecting antineutrinos. Davis was the lead scientist behind the Homestake Experiment, the large-scale radiochemical neutrino detector which first detected evidence of neutrinos from the sun.

He shared the Nobel Prize in Physics in 2002 with Japanese physicist Masatoshi Koshiba and American Riccardo Giacconi for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos, looking at the solar neutrino problem in the Homestake Experiment. He was almost 88 years old when awarded the prize, making him the oldest ever recipient of a Nobel Prize.

Personal life

Davis met his wife Anna Torrey at Brookhaven and together they built a 21-foot wooden sailboat, the Halcyon. They had five children and lived in the same house in Blue Point, New York for over 50 years. He died in Blue Point, New York from Alzheimer's Disease.

Honours and awards

• Cyrus B. Comstock Prize of the National Academy of Sciences (1978)
• Tom W. Bonner Prize of the American Physical Society (1988)
• W. K. H. Panofsky Prize of the American Physical Society (1992)
• Beatrice M. Tinsley Prize of the American Astronomical Society (1994)
• George Ellery Hale Prize of the American Astronomical Society (1996)
• Wolf Prize in Physics (2000)
• National Medal of Science (2001)
• Nobel Prize in Physics (2002)

Notable works

• Davis, Raymond, Jr. (1953). "Attempt to detect the Antineutrinos from a Nuclear Reactor by the ³⁷Cl (nu bar, e) ³⁷Ar Reaction". Physical Review 97. -- Non-detection of antineutrinos with chlorine
• Davis, Raymond, Jr. (1964). "Solar Neutrinos II, Experimental". Physical Review Letters 12. -- Proposal for Homestake Experiment
• Cleveland, B. T. et al (1998). "Measurement of the solar electron neutrino flux with the Homestake chlorine detector". Astrophysical Journal 496. -- final results of Homestake Experiment

References

• Kenneth Chang. "Raymond Davis Jr., Nobelist Who Caught Neutrinos, Dies at 91", The New York Times, 2 June 2006. Retrieved on 2007-10-10. 
• David B. Caruso. "Raymond Davis, who detected elusive solar particles, dies at 91", The Boston Globe, 2 June 2006. Retrieved on 2007-10-10.