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 scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...

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 in the 1960s-1980s, which was the first experiment to detect neutrinos emitted from the Sun; for this he shared the 2002

Nobel Prize in Physics ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then " ...

Early life and education

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

photographer A photographer (the Greek φῶς (''phos''), meaning "light", and γραφή (''graphê''), meaning "drawing, writing", together meaning "drawing with light") is a person who makes photographs. Duties and types of photographers As in oth ...

for the National Bureau of Standards. 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. Founded in 1856, UMD is the flagship institution of the University System of ...

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 research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the w ...

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, statistica ...

in 1942.

Career

Davis spent most of the war years at Dugway Proving Ground,

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

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, particu ...

basin for evidence of its predecessor,

Lake Bonneville Lake Bonneville was the largest Late Pleistocene paleolake in the Great Basin of western North America. It was a pluvial lake that formed in response to an increase in precipitation and a decrease in evaporation as a result of cooler temperature ...

. Upon his discharge from the army in 1946, Davis went to work at Monsanto's Mound Laboratory, in

Miamisburg, Ohio Miamisburg ( ) is a city in Montgomery County, Ohio. The population was 20,181 at the time of the 2010 census. A suburb of Dayton. It is part of the Dayton metropolitan area. Miamisburg is known for its large industry (mainly for its nucle ...

, 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 ...

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 U.S. Congress to foster and control the peacetime development of atomic science and technology. President ...

. In 1948, he joined Brookhaven National Laboratory, which was dedicated to finding 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 b ...

. 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 In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

, 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 tetrachloromethane, also recognised by the IUPAC, carbon tet in the cleaning industry, Halon-104 in firefighting, and Refrigerant-10 in HVACR) is an organic compound with the chemi ...

as detectors, Davis characterized the rate of the production of

argon Argon is a chemical element with the 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 a ...

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

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 said, Astrophysics "seeks to ascertain the nature of the h ...

, in particular for the detection of cosmic

neutrino A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...

s, looking at the

solar neutrino problem The solar neutrino problem concerned a large discrepancy between the flux of solar neutrinos as predicted from the Sun's luminosity and as measured directly. The discrepancy was first observed in the mid-1960s and was resolved around 2002. The fl ...

in the Homestake Experiment. 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. He died in

Blue Point, New York Blue Point is a hamlet and census-designated place in Suffolk County on Long Island, New York, United States. The population was 5,156 at the 2020 census. Blue Point is in the Town of Brookhaven. Geography According to the United States Cens ...

, from

Alzheimer's disease Alzheimer's disease (AD) is a neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in remembering recent events. As ...

Honors and awards

Comstock Prize in Physics The Comstock Prize in Physics is awarded by the U.S. National Academy of Sciences "for recent innovative discovery or investigation in electricity, magnetism, or radiant energy, broadly interpreted." Honorees must be residents of North America ...

of the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, 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 Nat ...

(1978) *

Tom W. Bonner Prize The Tom W. Bonner Prize in Nuclear Physics is an annual prize awarded by the American Physical Society, American Physical Society's Division of Nuclear Physics. Established in 1964, and currently consisting of $10,000 and a certificate, the Bonner ...

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 k ...

(1988) * W. K. H. Panofsky Prize of the American Physical Society (1992) * 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 ...

(1994) * George Ellery Hale Prize of the American Astronomical Society (1996) *

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 ...

(2000) * National Medal of Science (2001)National Science Foundation – The President's National Medal of Science
/ref> *

(2002) * Benjamin Franklin Medal (2003)

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"
Brookhaven National Laboratory (BNL), (December 1964). *Davis, R. Jr
"Search for Neutrinos from the Sun"
Brookhaven National Laboratory (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 manages the research and development of nuclear power and nuclear weapons in the United States ...

(through predecessor agency the Atomic Energy Commission), (1968). *Davis, R. Jr. & J.C. Evans Jr
"Report on the Brookhaven Solar Neutrino Experiment"
Brookhaven National Laboratory (BNL), (September 22, 1976). *Davis, R. Jr., Evans, J. C. & B. T. Cleveland
"Solar Neutrino Problem"
Brookhaven National Laboratory (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 (also known as Penn or UPenn) is a Private university, private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest- ...

Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...

(LANL), Brookhaven National Laboratory (BNL), (August 2, 1987).

References

External links

* including the Nobel Lecture on December 8, 2002 ''A Half-Century with Solar Neutrinos''
Raymond Davis Jr.
Brookhaven National Lab Web site
Neutrino web
at PBS

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

The Raymond Davis Scholarship
Society for Imaging Science and Technology
Kenneth Lande, "Raymond Davis", Biographical Memoirs of the National Academy of Sciences (2018)
{{DEFAULTSORT:Davis, Raymond Jr. 1914 births 2006 deaths American Nobel laureates 20th-century American physicists Deaths from Alzheimer's disease 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 Winners of the Panofsky Prize People from Blue Point, New York Scientists from New York (state) Deaths from dementia in New York (state)