Yvette Cauchois (; 19 December 1908 – 19 November 1999) was a French

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 ...

known for her contributions to

x-ray spectroscopy X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. Characteristic X-ray spectroscopy When an electron from the inner shell of an atom is excited by the energy o ...

and

x-ray optics X-ray optics is the branch of optics that manipulates X-rays instead of visible light. It deals with focusing and other ways of manipulating the X-ray beams for research techniques such as X-ray crystallography, X-ray fluorescence, small-angle X-ray ...

, and for pioneering European synchrotron research.

Education

Cauchois attended school in Paris, and pursued undergraduate studies at the

Sorbonne Sorbonne may refer to: * Sorbonne (building), historic building in Paris, which housed the University of Paris and is now shared among multiple universities. *the University of Paris (c. 1150 – 1970) *one of its components or linked institution, ...

who awarded her a degree in the physical sciences in July 1928. Cauchois undertook graduate studies at the Laboratory of Physical Chemistry with the support of a National Fund for Science studentship, and was awarded her

doctorate A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism ''li ...

in 1933 for her work on the use of curved crystals for

high-resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how cl ...

x-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

analysis.

Academic career

After completing her doctoral studies, Cauchois was appointed research assistant in the laboratory of Jean Perrin at the Centre national de la recherche scientifique (CNRS). She was promoted to research associate in 1937, and in the same year participated in the launch of the '' Palais de la Découverte''. In January 1938 Cauchois was named head of the Physical Chemistry Laboratory in the Faculty of Sciences of

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), ma ...

. When

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

broke out, Cauchois maintained continuity at the Laboratory, acting as Head of Studies when Jean Perrin had to flee to the United States. In 1945, when the

Liberation Liberation or liberate may refer to: Film and television * ''Liberation'' (film series), a 1970–1971 series about the Great Patriotic War * "Liberation" (''The Flash''), a TV episode * "Liberation" (''K-9''), an episode Gaming * '' Liberati ...

led to the dismissal of Louis Dunoyer de Segonzac, Cauchois was promoted to Professor at the

. She became Chair of Chemical Physics in 1954, succeeding

Edmond Bauer Edmond Bauer (26 October 1880 – 17 October 1963) was a French physicist who was a student of Marie Curie and Paul Langevin who made studies on radiation in his early career. He was from a Jewish family and suffered during World War II during th ...

to take charge of the laboratory. With the number of researchers outgrowing the available space in the Laboratory, Cauchois founded the ''Centre de Chimie Physique'' at

Orsay Orsay () is a commune in the Essonne department in Île-de-France in northern France. It is located in the southwestern suburbs of Paris, France, from the centre of Paris. A fortified location of the Chevreuse valley since the 8th centur ...

in 1960. She directed this organisation for ten years, whilst simultaneously continuing her work at the Sorbonne. She joined the

University of Paris VI Pierre and Marie Curie University (french: link=no, Université Pierre-et-Marie-Curie, UPMC), also known as Paris 6, was a public research university in Paris, France, from 1971 to 2017. The university was located on the Jussieu Campus in the L ...

in 1971 following the division of the

. Cauchois chaired the French Society of Physical Chemistry from 1975–1978. She was only the second woman to do so, after

Marie Curie Marie Salomea Skłodowska–Curie ( , , ; born Maria Salomea Skłodowska, ; 7 November 1867 – 4 July 1934) was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity. She was the first ...

. From 1978 until her retirement in 1983, Cauchois was Professor Emeritus at the

. Cauchois was still conducting active laboratory research as late as 1992 (aged 83). Over her lifetime she produced more than 200 publications, which continue to be cited today.

Research on x-rays and crystals

In the early 1930s, Cauchois established the fundamental principles of a new

x-ray spectrometer X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation. Characteristic X-ray spectroscopy When an electron from the inner shell of an atom is excited by the energy ...

that was both easy to use and had a

high resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how ...

, satisfying the

Bragg reflection In physics and chemistry , Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave ...

condition. The new spectrometer was named after her, and from 1934 she used it to observe gas emissions and

multiplet In physics and particularly in particle physics, a multiplet is the state space for 'internal' degrees of freedom of a particle, that is, degrees of freedom associated to a particle itself, as opposed to 'external' degrees of freedom such as the ...

s. The new technique was used around the world for the analysis of x-rays and

gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

s and prompted a wave of new scholarship in radiation studies. Cauchois pioneered developments in x-ray imaging and observed that x-ray radiation could be focused using curved crystal for use in

monochromator A monochromator is an optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input. The name is from the Greek roots ''mono-'', "s ...

s and

x-ray scattering X-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystal structure, chemical composition, and physical properties of materials and thin films. These techniques are based on observ ...

. Cauchois' work on soft x-ray distributions was the first step in determining the photo-absorption spectra. She used the radiation reflected from crystals to study the electronic structure of materials. Cauchois systematically studied the

spectra of

heavy element upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...

s and

actinide The actinide () or actinoid () series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The actinide series derives its name from the first element in the series, actinium. The info ...

s. In 1936, Cauchois and

Horia Hulubei Horia Hulubei (; 15 November 1896 – 22 November 1972) was a Romanian nuclear physicist, known for his contributions to the development of X-ray spectroscopy. Education and military service Born in Iași, he graduated in 1915 first in his clas ...

claimed to have discovered element 85 via X-ray analysis, conducting further research and publishing on follow-up studies in 1939. With McTaggart in 1948 she determined the differential absorption of X-rays by Zirconium and Hafnium.Cauchols Y. et McTaggart K. (1949) 'Doslmétrle par absorption dl!férentlelle des rayons X, à l'aide de spectromètres à cristaux courbés et de computeurs de Geiger.' Extrait des Comptes rendus des séances de l'Academie des Sciences, séance du 21 mars 1949. C.R. 228:1003 Cauchois,

Sonia Cotelle Sonia Cotelle, née Slobodkine (19 June 1896 – 18 January 1945), was a Polish Radiochemistry, radiochemist. Life and work Sonia Cotelle was born in Warsaw, capital of the Vistula Land, in the Russian Empire on 19 June 1896. She was married, bu ...

, and Hulubei proved the presence of

polonium Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...

and

neptunium Neptunium is a chemical element with the symbol Np and atomic number 93. A radioactive actinide metal, neptunium is the first transuranic element. Its position in the periodic table just after uranium, named after the planet Uranus, led to it bein ...

, and Cauchois later pioneered studies on the x-ray spectra of

transuranic elements The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, which is the atomic number of uranium. All of these elements are unstable and decay radioactively into other elements. ...

. A fascination with astrophysics led Cauchois to study extraterrestrial x-ray radiation, especially the solar x-ray spectrum using missile experiments. In 1970 she produced x-ray images of the sun.

Synchrotron and solar research

From 1962, Cauchois initiated a research programme in collaboration with the ''

Istituto Superiore di Sanità The ''Istituto Superiore di Sanità'' (Italian National Institute of Health, literally 'Higher Health Institute'), also ISS, is an Italian public institution that, as the leading technical-scientific body of the Italian National Health Service (' ...

'' at the ''

Laboratori Nazionali di Frascati The INFN National Laboratory of Frascati (LNF) was founded in 1954 with the objective of furthering particle physics research, and more specifically to host the 1.1 GeV electrosynchrotron, the first accelerator ever built in Italy. The Labo ...

'' to explore the possibilities of synchrotron research. She was the first person in Europe to realise the potential of the radiation emitted by electrons rotating in the synchrotron as a source for understanding the properties of matter. In the early 1970s, Cauchois carried out her experiments at LURE (''Laboratoire pour l'utilisation des radiations électromagnétiques'').

Personal life and death

Cauchois was particularly interested in assisting young and underprivileged people. She also enjoyed poetry and music, and was a skilled

grand piano The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keybo ...

player. After meeting a priest from the monastery of Bârsana and discussing religious themes with him, Cauchois decided to be baptized in the Orthodox religion. She travelled to Maramures, Romania in 1999, aged 90, and was baptized there. Cauchois contracted

bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...

on this trip, and died a few days after returning to

. She was buried in the Monastery Bârsana, to whom she

bequeath Historically, a bequest is personal property given by will and a devise is real property given by will. Today, the two words are often used interchangeably. The word ''bequeath'' is a verb form for the act of making a bequest. Etymology Bequest c ...

ed her assets.

Awards

* Ancel Prize from the '' Société chimique de France'' (1933) * Henri Becquerel Prize from the French Academy of Sciences (1935) * Gizbal-Baral Prize (10,000 francs) from the French Academy of Sciences (1936) *

Henry de Jouvenel Henry de Jouvenel des Ursins (5 April 1876 – 5 October 1935) was a French journalist and statesman.

Prize for selfless scientific activity (10,000 francs) from the Ministry of National Education (France) (1938) * Jerome Ponti Prize from the French Academy of Sciences (1942) * Triossi Prize from the French Academy of Sciences (1946) * Commander of the Order of the Ministry of Education * Officer of the

Legion of Honour The National Order of the Legion of Honour (french: Ordre national de la Légion d'honneur), formerly the Royal Order of the Legion of Honour ('), is the highest French order of merit, both military and civil. Established in 1802 by Napoleon ...

* Officer of the National Order of Merit (France) * Medal of the Czechoslovak Society of Spectroscopy (1974) * Fellow of

The Optical Society Optica (formerly known as The Optical Society (OSA) and before that as the Optical Society of America) is a professional society of individuals and companies with an interest in optics and photonics. It publishes journals and organizes conferenc ...

(1974) * Gold medal of the University of Paris (1987) * Doctor ''honoris causa'' of the University of Bucharest (1993) * Cauchois' name was given to a street of the new university area of Moulon in

Gif-sur-Yvette Gif-sur-Yvette (, literally ''Gif on Yvette'') is a commune in south-western Ile de France, France. It is located from the center of Paris. Geography The town is crossed by and named after the river Yvette. The total area is and is green s ...

and a street in

Tomblaine Tomblaine () is a commune in the Meurthe-et-Moselle department in north-eastern France. Stage 7 of the Tour de France on 7 July 2012 started in Tomblaine. The Stade Marcel Picot, football stadium to Ligue 1 side AS Nancy, is located within t ...

(

Meurthe-et-Moselle Meurthe-et-Moselle () is a department in the Grand Est region of France, named after the rivers Meurthe and Moselle. It had a population of 733,760 in 2019.Jean Perrin *

* Christiane Bonnelle *

References

{{DEFAULTSORT:Cauchois, Yvette 1908 births 1999 deaths French women physicists Officiers of the Légion d'honneur Scientists from Paris University of Paris faculty Infectious disease deaths in Romania 20th-century French physicists 20th-century French women scientists Paris-Sorbonne University faculty Fellows of the Optical Society Deaths from bronchitis Women in optics