Horia Hulubei (; 15 November 1896 – 22 November 1972) was a

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

nuclear physicist Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the ...

, known for his contributions to the development of

X-ray spectroscopy X-ray spectroscopy is a general term for several Spectroscopy, 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 b ...

Education and military service

Born in

Iași Iași ( , , ; also known by other #Etymology and names, alternative names), also referred to mostly historically as Jassy ( , ), is the Cities in Romania, third largest city in Romania and the seat of Iași County. Located in the historical ...

, he graduated in 1915 first in his class at the Boarding High School of Iași. He then enrolled in the Faculty of Sciences at the

University of Iași The Alexandru Ioan Cuza University (; acronym: UAIC) is a public university located in , Romania. Founded by an 1860 decree of Prince Alexandru Ioan Cuza, under whom the former was converted to a university, the University of , as it was named ...

, but his studies were interrupted by the entry of Romania in

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

; conscripted into the army, he fought as a second lieutenant at the battles of

Nămoloasa Nămoloasa is a commune in Galați County, in the Western Moldavia region of Romania. It is composed of three villages: Crângeni, Nămoloasa, and Nămoloasa-Sat. The commune is located in the south-west of the county, on the border with Brăila C ...

, Băltăreți, and

Mărășești Mărășești () is a small town in Vrancea County, Western Moldavia, Romania. It administers six villages: Călimănești, Haret, Modruzeni, Pădureni, Siretu, and Tișița. Geography The town is located in the eastern part of the county, on th ...

in the summer of 1917. General

Henri Mathias Berthelot Henri Mathias Berthelot (7 December 1861 – 29 January 1931) was a French general during World War I. He held an important staff position under Joseph Joffre, the French commander-in-chief, at the First Battle of the Marne, before later commandin ...

, the head of the French military mission to Romania, decided to send a group of young Romanians (including Hulubei) to France to train at an aviation school; upon completing the training, Hulubei participated as a pilot on a

fighter aircraft Fighter aircraft (early on also ''pursuit aircraft'') are military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air supremacy, air superiority of the battlespace. Domina ...

of the French Air Service on the Western Front. Gravely wounded, he was awarded the

Legion of Honour The National Order of the Legion of Honour ( ), formerly the Imperial Order of the Legion of Honour (), is the highest and most prestigious French national order of merit, both military and Civil society, civil. Currently consisting of five cl ...

. Upon returning to Romania, he worked for a while in civil aviation, and helped start the first Romanian air service, connecting

Istanbul Istanbul is the List of largest cities and towns in Turkey, largest city in Turkey, constituting the country's economic, cultural, and historical heart. With Demographics of Istanbul, a population over , it is home to 18% of the Demographics ...

to Bucharest to

Budapest Budapest is the Capital city, capital and List of cities and towns of Hungary, most populous city of Hungary. It is the List of cities in the European Union by population within city limits, tenth-largest city in the European Union by popul ...

. In 1922 he returned to his studies in physics and chemistry, completing in 1926 his undergraduate degree at the University of Iași, ''

magna cum laude Latin honors are a system of Latin phrases used in some colleges and universities to indicate the level of distinction with which an academic degree has been earned. The system is primarily used in the United States. It is also used in some Sout ...

''. He then went to

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

for his graduate studies, obtaining his Ph.D. from

Paris-Sorbonne University Paris-Sorbonne University (also known as Paris IV; ) was a public university, public research university in Paris, France, active from 1971 to 2017. It was the main inheritor of the Faculty of Humanities of the University of Paris. In 2018, it m ...

, where his advisor was the

Nobel laureate The Nobel Prizes (, ) are awarded annually by the Royal Swedish Academy of Sciences, the Swedish Academy, the Karolinska Institutet, and the Norwegian Nobel Committee to individuals and organizations who make outstanding contributions in th ...

Jean Perrin. His Ph.D. thesis with the title ''"Contribution to the study of quantum diffusion of X-rays"'' was defended in 1933 in Paris in front of an examination committee chaired by Nobel laureate

Marie Curie Maria Salomea Skłodowska-Curie (; ; 7 November 1867 – 4 July 1934), known simply as Marie Curie ( ; ), was a Polish and naturalised-French physicist and chemist who conducted pioneering research on radioactivity. She was List of female ...

. Afterwards he continued his research at the

University of Paris The University of Paris (), known Metonymy, metonymically as the Sorbonne (), was the leading university in Paris, France, from 1150 to 1970, except for 1793–1806 during the French Revolution. Emerging around 1150 as a corporation associated wit ...

, staying in contact with the likes of

Frédéric Joliot-Curie Jean Frédéric Joliot-Curie (; ; 19 March 1900 – 14 August 1958) was a French chemist and physicist who received the 1935 Nobel Prize in Chemistry with his wife, Irène Joliot-Curie, for their discovery of induced radioactivity. They were t ...

Paul Langevin Paul Langevin (23 January 1872 – 19 December 1946) was a French physicist who developed Langevin dynamics and the Langevin equation. He was one of the founders of the '' Comité de vigilance des intellectuels antifascistes'', an anti-fascist ...

, and

Albert Einstein Albert Einstein (14 March 187918 April 1955) was a German-born theoretical physicist who is best known for developing the theory of relativity. Einstein also made important contributions to quantum mechanics. His mass–energy equivalence f ...

Scientific achievements

Between 1927 and 1938, he worked alternately in Paris and at the University of Iași, where he established the first laboratory of the structure of matter in Romania. With the help of his advanced X-ray spectroscopy equipment he observed several previously unidentified X-ray spectral lines, and subsequently came to the decision that such lines are associated with new elements. In 1936, Hulubei together with Yvette Cauchois claimed to have discovered element 85 via X-ray analysis, conducting further research and publishing on follow-up studies in 1939. With Cauchois and Sonia Cotelle, he established the presence of

polonium Polonium is a chemical element; it has symbol Po and atomic number 84. A rare and highly radioactive metal (although sometimes classified as a metalloid) with no stable isotopes, polonium is a chalcogen and chemically similar to selenium and tel ...

and

neptunium Neptunium is a chemical element; it has chemical symbol, symbol Np and atomic number 93. A radioactivity, radioactive actinide metal, neptunium is the first transuranic element. It is named after Neptune, the planet beyond Uranus in the Solar Syste ...

. Hulubei also claimed and published the discovery of a new element, "moldavium", in 1936, the discovery of "sequanium" in 1939, and that of "dor" in 1945. Later, however, it was shown that the reported X-ray lines did not belong to new elements. Hulubei's samples for "dor" did contain the real element 85 (

astatine Astatine is a chemical element; it has Symbol (chemistry), symbol At and atomic number 85. It is the abundance of elements in Earth's crust, rarest naturally occurring element in the Earth's crust, occurring only as the Decay chain, decay product ...

), but his means to detect it were too weak, by current standards, to enable correct identification; moreover, he could not perform chemical tests on the element. For his many scientific achievements the in Romania (NIPNE/IFIN-HH) was named after him. He was the Founder and First Director of the (IFA) in

Măgurele Măgurele is a town situated in the southwestern part of Ilfov County, Muntenia, Romania. It has a population of 14,414 as of 2021 and hosts several research institutes. In 2024, new buses were donated from the Voluntari district. It is rapidly ...

in 1949. Elected corresponding member of the

Romanian Academy The Romanian Academy ( ) is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 active members who are elected for life. According to its bylaws, the academy's ma ...

in 1937, Hulubei became a titular member in 1946. Stripped of membership by the new

communist regime A communist state, also known as a Marxist–Leninist state, is a one-party state in which the totality of the power belongs to a party adhering to some form of Marxism–Leninism, a branch of the communist ideology. Marxism–Leninism was ...

in 1948, he was restored to the Academy in 1955. Hulubei was also corresponding member (from 1935) and titular member (from 1941) of the Romanian Academy of Sciences, and served as Vice-President of the organization in 1947–48.

University teaching

During the early 1960s and 1970s Hulubei was a Professor of Atomic Physics in the Department of Atomic and Nuclear Physics of the Faculty of Physics at the

University of Bucharest The University of Bucharest (UB) () is a public university, public research university in Bucharest, Romania. It was founded in its current form on by a decree of Prince Alexandru Ioan Cuza to convert the former Princely Academy of Bucharest, P ...

, where he delivered elegant and clear lectures on the

Compton effect Compton scattering (or the Compton effect) is the quantum theory of high frequency photons scattering following an interaction with a charged particle, usually an electron. Specifically, when the photon hits electrons, it releases loosely bound e ...

and inelastic Compton scattering/ resonant inelastic X-ray scattering (RIXS).

Publications

* * * * ''Course Notes of Physical Chemistry'', Editura Academiei, Bucharest, 1940. ( "Curs de chimie fizică "(1940)) * ''X-ray Spectroscopy'' ("Spectroscopia X"). (1948) * ''The Structure of Matter.'' "Structura materiei" (1950)

References

External links

Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN HHLibrary of Congress
{{DEFAULTSORT:Hulubei, Horia 1896 births 1972 deaths Alexandru Ioan Cuza University alumni University of Paris alumni Romanian nuclear physicists Rectors of the University of Bucharest Titular members of the Romanian Academy Members of the Romanian Academy of Sciences Fellows of the American Physical Society Academic staff of the University of Bucharest Romanian military personnel of World War I Romanian World War I pilots Recipients of the Legion of Honour Academic staff of Alexandru Ioan Cuza University