Raymond Davis Jr. (October 14, 1914 – May 31, 2006) was an American

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

and

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 ...

. He is best known as the leader of the

Homestake experiment The Homestake experiment (sometimes referred to as the Davis experiment or Solar Neutrino Experiment and in original literature called Brookhaven Solar Neutrino Experiment or Brookhaven 37Cl (Chlorine) Experiment) was an experiment headed by astr ...

in the 1960s-1980s, which was the first experiment to detect

neutrinos A neutrino ( ; denoted by the Greek letter ) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that it ...

emitted from the Sun; for this he shared the 2002

Nobel Prize in Physics The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the ...

Early life and education

Davis was born in Washington, D.C., where his father was a photographer for the

National Bureau of Standards The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sc ...

. He spent several years as a choirboy 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 received his B.S. from the

University of Maryland The University of Maryland, College Park (University of Maryland, UMD, or simply Maryland) is a public land-grant research university in College Park, Maryland, United States. Founded in 1856, UMD is the flagship institution of the Univ ...

in 1938 in chemistry, which is part of the University of Maryland College of Computer, Mathematical, and Natural Sciences. He also received a master's degree from that school and a Ph.D. from

Yale University Yale University is a Private university, private Ivy League research university in New Haven, Connecticut, United States. Founded in 1701, Yale is the List of Colonial Colleges, third-oldest institution of higher education in the United Stat ...

physical chemistry Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mech ...

in 1942.

Career

Davis spent most of the war years at

Dugway Proving Ground Dugway Proving Ground (DPG) is a United States Army facility established in 1942 to test biological and chemical weapons, located about southwest of Salt Lake City, Utah and south of the Utah Test and Training Range. Location Dugway Provin ...

Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...

observing the results of chemical weapons tests and exploring the

Great Salt Lake The Great Salt Lake is the largest saltwater lake in the Western Hemisphere and the eighth-largest terminal lake in the world. It lies in the northern part of the U.S. state of Utah and has a substantial impact upon the local climate, partic ...

basin for evidence of its predecessor, Lake Bonneville. After his discharge from the army in 1945, Davis went to work at

Monsanto The Monsanto Company () was an American agrochemical and agricultural biotechnology corporation founded in 1901 and headquartered in Creve Coeur, Missouri. Monsanto's best-known product is Roundup, a glyphosate-based herbicide, developed ...

's Mound Laboratory, in Miamisburg, Ohio, doing applied

radiochemistry Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads t ...

of interest to the

United States Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by the U.S. Congress to foster and control the peacetime development of atomic science and technology. President Harry ...

. In 1948, he joined

Brookhaven National Laboratory Brookhaven National Laboratory (BNL) is a United States Department of Energy national laboratories, United States Department of Energy national laboratory located in Upton, New York, a hamlet of the Brookhaven, New York, Town of Brookhaven. It w ...

, which was attempting to find peaceful uses for

nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...

. Davis reports that he was asked "to find something interesting to work on," and dedicated his career to the study of

, particles which had been predicted to explain the process of

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which an atomic nucleus emits a beta particle (fast energetic electron or positron), transforming into an isobar of that nuclide. For example, beta decay of a neutron ...

, but whose separate existence had not been confirmed. Davis investigated the detection of neutrinos by 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 beta decay that would mimic the signal of neutrinos. Using barrels and tanks of

carbon tetrachloride Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also IUPAC nomenclature of inorganic chemistry, recognised by the IUPAC), is a chemical compound with the chemical formula CCl4. It is a n ...

as detectors, Davis characterized the rate of the production of

argon Argon is a chemical element; it has symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...

-37 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 Homestake experiment (sometimes referred to as the Davis experiment or Solar Neutrino Experiment and in original literature called Brookhaven Solar Neutrino Experiment or Brookhaven 37Cl (Chlorine) Experiment) was an experiment headed by astr ...

, the large-scale radiochemical neutrino detector which first detected evidence of neutrinos from the sun. Davis shared the

in 2002 with Japanese physicist Masatoshi Koshiba and Italian

Riccardo Giacconi Riccardo Giacconi ( , ; October 6, 1931 – December 9, 2018) was an Italian-American Nobel Prize-winning astrophysicist who laid down the foundations of X-ray astronomy. He was a professor at the Johns Hopkins University. Biography Born in ...

for pioneering contributions to

astrophysics Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, astrophysics "seeks to ascertain the ...

, Davis was recognized for his work on the detection of cosmic

neutrino A neutrino ( ; denoted by the Greek letter ) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small ('' -ino'') that i ...

s, looking at the solar neutrino problem in the

. He was 88 years old when awarded the 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. On May 31, 2006, he died in

Blue Point, New York Blue Point is a Hamlet (New York), hamlet and census-designated place in Suffolk County, New York, Suffolk County on Long Island, New York (state), New York, United States. The population was 5,156 at the 2020 United States census, 2020 census. Bl ...

, from complications of

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease and the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As the disease advances, symptoms can include problems wit ...

Honors and awards

*2003, Benjamin Franklin Medal (with John N. Bahcall and Masatoshi Koshiba) *2002,

(with Masatoshi Koshiba) *2001,

National Medal of Science The National Medal of Science is an honor bestowed by the President of the United States to individuals in science and engineering who have made important contributions to the advancement of knowledge in the fields of behavioral science, behavior ...

*2000,

Wolf Prize in Physics The Wolf Prize in Physics is awarded once a year by the Wolf Foundation in Israel. It is one of the six Wolf Prizes established by the Foundation and awarded since 1978; the others are in Agriculture, Chemistry, Mathematics, Medicine and Arts. The ...

*1996, George Ellery Hale Prize of the American Astronomical Society *1994, Beatrice M. Tinsley Prize of the

American Astronomical Society The American Astronomical Society (AAS, sometimes spoken as "double-A-S") is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC. The primary objective of the AAS is to promote the adv ...

*1992, W. K. H. Panofsky Prize of the American Physical Society *1988, Tom W. Bonner Prize of the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

*1978, Comstock Prize in Physics of the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

Notable works

* – Non-detection of antineutrinos with chlorine * – Proposal for Homestake Experiment * – final results of Homestake Experiment

Other publications

*Davis, R. Jr. & D. S. Harmer
"Solar Neutrinos"

(BNL), (December 1964). *Davis, R. Jr
"Search for Neutrinos from the Sun"

(BNL),

United States Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear w ...

(through predecessor agency the Atomic Energy Commission), (1968). *Davis, R. Jr. & J.C. Evans Jr
"Report on the Brookhaven Solar Neutrino Experiment"

(BNL), (September 22, 1976). *Davis, R. Jr., Evans, J. C. & B. T. Cleveland
"Solar Neutrino Problem"

(BNL), (April 28, 1978). *Davis, R. Jr., Cleveland, B. T. & J. K. Rowley
"Variations in the Solar Neutrino Flux"
Department of Astronomy and Astrophysics at

University of Pennsylvania The University of Pennsylvania (Penn or UPenn) is a Private university, private Ivy League research university in Philadelphia, Pennsylvania, United States. One of nine colonial colleges, it was chartered in 1755 through the efforts of f ...

Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...

(LANL),

(BNL), (August 2, 1987).

References

External links

* including the Nobel Lecture on December 8, 2002 ''A Half-Century with Solar Neutrinos''
The Ghost Particle
at

PBS The Public Broadcasting Service (PBS) is an American public broadcaster and non-commercial, free-to-air television network based in Arlington, Virginia. PBS is a publicly funded nonprofit organization and the most prominent provider of educat ...

NOVA A nova ( novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", Latin for "new") that slowly fades over weeks or months. All observed novae involve white ...

{{DEFAULTSORT:Davis, Raymond Jr. 1914 births 2006 deaths American Nobel laureates 20th-century American physicists Deaths from Alzheimer's disease in New York (state) Enrico Fermi Award recipients Members of the United States National Academy of Sciences National Medal of Science laureates Nobel laureates in Physics Scientists from Washington, D.C. American physical chemists University of Maryland, College Park alumni Winners of the Beatrice M. Tinsley Prize Wolf Prize in Physics laureates Yale Graduate School of Arts and Sciences alumni University of Pennsylvania faculty Fellows of the American Physical Society Brookhaven National Laboratory Nobel laureates Brookhaven National Laboratory staff Winners of the Panofsky Prize People from Blue Point, New York Scientists from New York (state) Deaths from dementia in New York (state) Benjamin Franklin Medal (Franklin Institute) laureates