Arthur B. McDonald

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Arthur B. McDonald

Arthur B. McDonald 5193-2015.jpg
Arthur B. McDonald in Stockholm in December 2015
Arthur Bruce McDonald

(1943-08-29) August 29, 1943 (age 75)
Residence Kingston, Ontario, Canada
Nationality Canadian
Alma mater
Known forSolving the solar neutrino problem
Scientific career
Fields Astrophysics
Thesis Excitation energies and decay properties of T = 3/2 states in 17O, 17F and 21Na.  (1970)
Doctoral advisor Charles A. Barnes

Arthur Bruce McDonald, CC OOnt ONS FRS FRSC P.Eng, (born August 29, 1943) is a Canadian astrophysicist. McDonald is the director of the Sudbury Neutrino Observatory Collaboration and held the Gordon and Patricia Gray Chair in Particle Astrophysics at Queen's University in Kingston, Ontario from 2006 to 2013. He was awarded the 2015 Nobel Prize in Physics jointly with Japanese physicist Takaaki Kajita.

Order of Canada order

The Order of Canada is a Canadian national order and the second highest honour for merit in the system of orders, decorations, and medals of Canada. It comes second only to membership in the Order of Merit, which is the personal gift of Canada's monarch.

Order of Ontario order

The Order of Ontario is the most prestigious official honour in the Canadian province of Ontario. Instituted in 1986 by Lieutenant Governor Lincoln Alexander, on the advice of the Cabinet under Premier David Peterson, the civilian order is administered by the Lieutenant Governor-in-Council and is intended to honour current or former Ontario residents for conspicuous achievements in any field.

The Order of Nova Scotia is a civilian honour for merit in the Canadian province of Nova Scotia. Instituted on 2 August 2001, when Lieutenant Governor Myra Freeman granted Royal Assent to the Order of Nova Scotia Act, the order is administered by the Governor-in-Council and is intended to honour current or former Nova Scotia residents for conspicuous achievements in any field, being thus described as the highest honour amongst all others conferred by the Nova Scotia Crown.


Early life

McDonald was born on August 29, 1943, [1] in Sydney, Nova Scotia. [3] He graduated with a B.Sc. in physics in 1964 and M.Sc. in physics in 1965 from Dalhousie University in Nova Scotia. [4] He then obtained his Ph.D. in physics in 1969 from the California Institute of Technology. [5] McDonald cited a high school math teacher and his first-year physics professor at Dalhousie as his inspirations for going into the field of physics. [6]

Sydney, Nova Scotia Urban Community in Nova Scotia, Canada

Sydney is an urban community located in the Cape Breton Regional Municipality of Cape Breton Island, Nova Scotia, Canada. Situated on Cape Breton Island's east coast, it belongs administratively to the Cape Breton Regional Municipality. Sydney was founded in 1785 by the British, was incorporated as a city in 1904, and dissolved on 1 August 1995, when it was amalgamated into the regional municipality.

Nova Scotia Province of Canada

Nova Scotia is one of Canada's three Maritime Provinces, and one of the four provinces that form Atlantic Canada. Its provincial capital is Halifax. Nova Scotia is the second-smallest of Canada's ten provinces, with an area of 55,284 square kilometres (21,300 sq mi), including Cape Breton and another 3,800 coastal islands. As of 2016, the population was 923,598. Nova Scotia is Canada's second-most-densely populated province, after Prince Edward Island, with 17.4 inhabitants per square kilometre (45/sq mi).

A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years, or a person holding such a degree.

Academic career

McDonald worked as a Research Officer at the Chalk River Nuclear Laboratories northwest of Ottawa from 1969 to 1982. He became professor of physics at Princeton University from 1982 to 1989, leaving Princeton to join Queen's University where he became Professor from 1989 to 2013.

Ottawa Federal capital city in Ontario, Canada

Ottawa is the capital city of Canada. It stands on the south bank of the Ottawa River in the eastern portion of southern Ontario. Ottawa borders Gatineau, Quebec; the two form the core of the Ottawa–Gatineau census metropolitan area (CMA) and the National Capital Region (NCR). As of 2016, Ottawa had a city population of 934,243 and a metropolitan population of 1,323,783 making it the fourth-largest city and the fifth-largest CMA in Canada. In June 2019, the City of Ottawa estimated it had surpassed a population of 1,000,000.

Princeton University University in Princeton, New Jersey

Princeton University is a private Ivy League research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution. The institution moved to Newark in 1747, then to the current site nine years later, and renamed itself Princeton University in 1896.

Queens University university in Kingston, Ontario, Canada

Queen's University at Kingston is a public research university in Kingston, Ontario, Canada. Founded on 16 October 1841, via a royal charter issued by Queen Victoria, the university predates Canada's founding by 26 years. Queen's holds more than 1,400 hectares of land throughout Ontario and owns Herstmonceux Castle in East Sussex, England. Queen's is organized into ten undergraduate, graduate, and professional faculties and schools.

McDonald was a visiting scientist at the European Organization for Nuclear Research (CERN) in Geneva in 2004. [7]

CERN International organization which operates the worlds largest particle physics laboratory

The European Organization for Nuclear Research, known as CERN, is a European research organization that operates the largest particle physics laboratory in the world. Established in 1954, the organization is based in a northwest suburb of Geneva on the Franco–Swiss border and has 23 member states. Israel is the only non-European country granted full membership. CERN is an official United Nations Observer.

Geneva Large city in Switzerland

Geneva is the second-most populous city in Switzerland and the most populous city of Romandy, the French-speaking part of Switzerland. Situated where the Rhône exits Lake Geneva, it is the capital of the Republic and Canton of Geneva.

In 2013 McDonald became Professor Emeritus of Queen's University in Kingston, Canada. He continues to be active in basic research in Neutrinos and Dark Matter at the SNOLAB underground Laboratory and as member of the Board of the Perimeter Institute for Theoretical Physics. [4] [8] [9]


SNOLAB is a Canadian underground physics laboratory at a depth of 2 km in Vale's Creighton nickel mine in Sudbury, Ontario. The original Sudbury Neutrino Observatory (SNO) experiment has ended, but the facilities have been expanded into a permanent underground laboratory.

Perimeter Institute for Theoretical Physics research institute in Canada

Perimeter Institute for Theoretical Physics is an independent research centre in foundational theoretical physics located in Waterloo, Ontario, Canada. It was founded in 1999. The Institute's founding and major benefactor is Canadian entrepreneur and philanthropist Mike Lazaridis.


McDonald presenting himself and his research

Physicists have been investigating whether or not neutrinos have mass. Since the late 1960s, experiments have hinted that neutrinos may have mass. Theoretical models of the Sun predict that neutrinos should be made in large numbers. Neutrino detectors on the Earth have repeatedly seen fewer than the expected number of neutrinos. Because neutrinos come in three varieties (electron, muon, and tau neutrinos), and because solar neutrino detectors have been primarily sensitive only to electron neutrinos, the preferred explanation over the years is that those "missing" neutrinos had changed, or oscillated, into a variety for which the detectors had little or no sensitivity. If a neutrino oscillates, according to the laws of quantum mechanics, then it must have a mass. [8]

Neutrino Elementary particle with very low mass that interacts only via the weak force and gravity

A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos, as leptons, do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.

Sun Star at the centre of the Solar System

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometers, or 109 times that of Earth, and its mass is about 330,000 times that of Earth. It accounts for about 99.86% of the total mass of the Solar System. Roughly three quarters of the Sun's mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.

Earth Third planet from the Sun in the Solar System

Earth is the third planet from the Sun and the only astronomical object known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4.5 billion years ago. Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth orbits around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times.

In 1984, McDonald's collaborator Herb Chen at the University of California at Irvine suggested the advantages of using heavy water as a detector for solar neutrinos. [10] Unlike previous detectors, using heavy water would make the detector sensitive to two reactions, one reaction sensitive to all neutrino flavours, the other sensitive to only the electron neutrino. Thus, such a detector could measure neutrino oscillations directly. Chen, McDonald, and collaborators formed the Sudbury Neutrino Observatory (SNO) to exploit this idea in 1984. [7] [11] SNO was to be a detector facility using 1000 tonnes of heavy water located 6,800 feet (2,100 m) underground in a mine outside Sudbury, Ontario. Chen died of leukemia in November 1987, however.

In August 2001, the Sudbury Neutrino Observatory, now led by McDonald, reported observations that directly suggested electron neutrinos from the Sun were oscillating into muon and tau neutrinos. McDonald is a co-recipient of the 2007 Benjamin Franklin Medal in Physics, the 2015 Nobel Prize in Physics, and the 2015 Fundamental Physics Prize for the discovery of neutrino oscillations and demonstrating that neutrinos have mass. [5] [12]

Honours and awards

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  1. 1 2 3 McDonald, Prof. Arthur Bruce. Who's Who. 2015 (online Oxford University Press ed.). A & C Black, an imprint of Bloomsbury Publishing plc.(subscription or UK public library membership required)(subscription required)
  2. 1 2 "Arthur McDonald biography". Royal Society. Retrieved 2015-10-09.
  3. "Past Winner 2003 NSERC Award of Excellence McDonald". Natural Sciences and Engineering Research Council of Canada. Retrieved 2012-09-21.
  4. 1 2 "CV Arthur B. McDonald" (PDF).
  5. 1 2 3 "Arthur B. McDonald". The Franklin Institute. Retrieved 6 October 2015.
  6. Gibson, Victoria (October 8, 2015). "Queen's professor awarded Nobel Prize". Queen's Journal. Retrieved December 25, 2017.
  7. 1 2 "The Nobel Prize in Physics 2015" . Retrieved 2016-12-15.
  8. 1 2 "Interview with Arthur B. McDonald". Archived from the original on 17 November 2007. Retrieved 2007-11-02.
  9. "Board of Directors". Perimeter Institute. 2012. Retrieved 2015-10-09.
  10. Chen, Herbert H. (September 1985). "Direct Approach to Resolve the Solar-Neutrino Problem". Physical Review Letters. 55 (14): 1534–1536. Bibcode:1985PhRvL..55.1534C. doi:10.1103/PhysRevLett.55.1534.
  11. Ewan, G.T.; Davidson, W.F. (2005). "Early Development of the Underground SNO Laboratory in Canada" (PDF). Physics in Canada. 61: 339–346, 347–350. Retrieved 13 December 2016.
  12. Spears, Tom (9 November 2015). "Neutrino Nobel winner Art McDonald nabs second big physics prize". Ottawa Citizen . Retrieved 9 November 2015.
  13. "Order of Canada citation".
  14. "Henry Marshall Tory Medal". Royal Society of Canada. Archived from the original on 2012-03-11. Retrieved 2012-09-21.
  15. "The Nobel Prize in Physics 2015".
  16. "Order of Canada Appointments". The Governor General of Canada His Excellency the Right Honourable David Johnston. Governor General of Canada . Retrieved 31 December 2015.
  17. National Academy of Sciences Members and Foreign Associates Elected, News from the National Academy of Sciences, National Academy of Sciences, May 3, 2016, retrieved 2016-05-14.
  18. "Order of Nova Scotia" . Retrieved 2016-12-08.
  19. (PDF) or empty |title= (help)