André Lagarrigue (1924 – 14 January 1975) was a French

particle physicist Particle physics or high-energy physics is the study of fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and ...

. Being the initiator of the

Gargamelle Gargamelle was a heavy liquid bubble chamber detector in operation at CERN between 1970 and 1979. It was designed to detect neutrinos and antineutrinos, which were produced with a beam from the Proton Synchrotron (PS) between 1970 and 1976, ...

experiment at

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...

, his work was of paramount importance in the discovery of neutral currents — the first experimental indication of the existence of the Z⁰ boson. This major discovery was a step towards verification of the

electroweak theory In particle physics, the electroweak interaction or electroweak force is the unified description of two of the fundamental interactions of nature: electromagnetism (electromagnetic interaction) and the weak interaction. Although these two forc ...

, today a pillar of the

Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

Career and research

Born in

Aurillac Aurillac (; ) is the prefecture of the Cantal department, in the Auvergne-Rhône-Alpes region of France. Geography Aurillac is at above sea level and located at the foot of the Cantal mountains in a small sedimentary basin. The city is b ...

, France, André Lagarrigue was admitted to

École Polytechnique (, ; also known as Polytechnique or l'X ) is a ''grande école'' located in Palaiseau, France. It specializes in science and engineering and is a founding member of the Polytechnic Institute of Paris. The school was founded in 1794 by mat ...

in Paris in 1945, specializing in the field of weapons engineering. However, while still a student at

he was attracted to the field of experimental physics, and participated in an experiment designed to determine the mass of the

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of ''ħ'', but with a much greater mass. It is classified as a ...

using a

cloud chamber A cloud chamber, also known as a Wilson chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic ...

. In 1952 he achieved a doctorate from the

Sorbonne University Sorbonne University () is a public research university located in Paris, France. The institution's legacy reaches back to the Middle Ages in 1257 when Sorbonne College was established by Robert de Sorbon as a constituent college of the Unive ...

on the experimental properties of muon decay. Between 1954 and 1955 he spent a sabbatical year at

Berkeley Berkeley most often refers to: *Berkeley, California, a city in the United States **University of California, Berkeley, a public university in Berkeley, California *George Berkeley (1685–1753), Anglo-Irish philosopher Berkeley may also refer to ...

, where he learnt of the experimental possibilities using

particle accelerators A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies to contain them in well-defined particle beam, beams. Small accelerators are used for fundamental ...

such as the

Bevatron The Bevatron was a particle accelerator — specifically, a Weak focusing, weak-focusing proton synchrotron — located at Lawrence Berkeley National Laboratory, U.S., which began operations in 1954. The antiproton was discovered there in ...

. After his return to France and École Polytechnique, he turned his focus towards

bubble chamber A bubble chamber is a vessel filled with a superheated transparent liquid (most often liquid hydrogen) used to detect electrically charged particles moving through it. It was invented in 1952 by Donald A. Glaser, for which he was awarded th ...

s, becoming renowned for his work on heavy liquid bubble chambers in a time where most physicist worked with

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

bubble chambers. Hydrogen bubble chambers would provide a pure proton target and consequently better measurements. The heavy liquid bubble chambers would however be cheaper and provide a high density of the target, suitable for

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 ...

detection, since neutrinos have a very small

cross-section Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture and engineering 3D * Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) ...

. Together with collaborators he constructed several heavy liquid bubble chambers at École Polytechnique. The first chamber built was called BP1, a

propane Propane () is a three-carbon chain alkane with the molecular formula . It is a gas at standard temperature and pressure, but becomes liquid when compressed for transportation and storage. A by-product of natural gas processing and petroleum ref ...

bubble chamber of 1 liter. They first used scattering at small angles, from light coming from the back of the chamber. They then tried to use side illumination at 90°, like in a cloud chamber. This method turned out to be efficient, and was later used in the

experiment. A second, bigger chamber, BP2, built for experiments at

Saclay Saclay () is a commune in the southwestern suburbs of Paris, France. It is located from the centre of Paris. It is best known for the large scientific facility CEA Saclay, mostly dealing with nuclear and particle physics. Population Inhabit ...

, contained 20 liters of a mixture of propane and

methyl iodide Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one h ...

. He went on to develop BP3. After attending a conference in 1963, on the newest developments in the field of

neutrino physics 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 ...

, Lagarrigue came up with the idea to construct a heavy liquid chamber for detection of

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 ...

— an idea that would earn him the nickname ''father of Gargamelle''. He wrote the first published proposal for Gargamelle, dated 10 February 1964, and gathered a collaboration consisting of seven laboratories: École Polytechnique Paris,

RWTH Aachen RWTH Aachen University (), in German ''Rheinisch-Westfälische Technische Hochschule Aachen'', is a German public research university located in Aachen, North Rhine-Westphalia, Germany. With more than 47,000 students enrolled in 144 study prog ...

, ULB Bruxelles, Istituto di Fisica dell'Università di Milano, LAL Orsay,

University College London University College London (Trade name, branded as UCL) is a Public university, public research university in London, England. It is a Member institutions of the University of London, member institution of the Federal university, federal Uni ...

and CERN. During the next years he led the collaboration to many important discoveries, amongst others that of the neutral currents in both

lepton In particle physics, a lepton is an elementary particle of half-integer spin (Spin (physics), spin ) that does not undergo strong interactions. Two main classes of leptons exist: electric charge, charged leptons (also known as the electron-li ...

ic and

hadron In particle physics, a hadron is a composite subatomic particle made of two or more quarks held together by the strong nuclear force. Pronounced , the name is derived . They are analogous to molecules, which are held together by the electri ...

ic events, and the experimental proof of the fractional charges of the

quarks A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly o ...

. Gargamelle turned out to be one of the most significant experiments in the history of CERN. In 1964 he became professor at the University of Orsay. In 1969 he became director of Orsay Linear Accelerator Laboratory, a position he held until his untimely death in 1975. Lagarrigue died of a heart attack, while leaving one of his courses at the University of Orsay.

Awards and honors

* In 1975 Lagarrigue was the second recipient of the Prize Ampère, awarded annually by the

French Academy of Sciences The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

. * A prize named in Lagarrigue's honor, The André Lagarrigue Prize, issued by the French Physics Society on the occasion of the 50th jubilee of Orsay Linear Accelerator Laboratory, is awarded annually to a senior

experimental physicist Experimental physics is the category of disciplines and sub-disciplines in the field of physics that are concerned with the observation of physical phenomena and experiments. Methods vary from discipline to discipline, from simple experiments and o ...

working in France. * An auditorium at

in Paris is named in his honor. * Lagarrigue has a

street A street is a public thoroughfare in a city, town or village, typically lined with Building, buildings on one or both sides. Streets often include pavements (sidewalks), pedestrian crossings, and sometimes amenities like Street light, streetligh ...

named after him at CERN, in the Prévessin site, and a square in the Meyrin site

Career and research

Awards and honors

References

Further reading