Emilio Gino Segre

Emilio Gino Segre was an Italian American physicist who was awarded the Nobel Prize in Physics in 1959 along with Owen Chamberlain. The Nobel Prize in Physics had been awarded to recipients from 1901. It is awarded annually during a formal ceremony held on December 10 by the Royal Swedish Academy of Sciences in Sweden, Stockholm.

Birth and early years

Emilio Gino Segre was born in Tivoli, Rome on February 1, 1905. He was the son of Guiseppe Segre, an industrialist and Amelia Treves. He spent a happy youth growing up in a well- to- do Jewish family originally from Northern Italy. He went to school in Tivoli and Rome. In 1922 he entered the University of Rome as a student of engineering. In 1927 he shifted from engineering to physics and completed his doctorate in physics in 1928 under the tutelage of Professor Enrico Fermi. His thesis was titled “Anomalous Dispersion and Magnetic Rotation”. He had the distinct honour of being the first student to be under Fermi’s sponsorship.

Early career

From 1928 to 1929 he served in the Italian army. In 1929 he joined the University of Rome as an assistant to Professor Carbino. In 1930 he obtained a Rockefeller Foundation fellowship and worked with Professor Otto Stern at Hamburg, Germany and with Professor Pieter Zeeman at Amsterdam, Holland. In 1932 he returned to Italy and was appointed as Assistant Professor in the University of Rome. Over here he worked with Professor Fermi and others. In 1936 he was appointed as the Director of the Physics Laboratory at the University of Palermo. He remained here till 1938.

Move to the United States of America

Emilio Segre disapproved the fascist rule of Benito Mussolini. Since he was a Jew, he could not retain his university position due to the anti- Semitic laws . So he accepted the job of a research assistant, which was offered by Ernest Lawrence. In 1938 Emilio Segre went to Berkley, California first as a research associate and later as a lecturer in the Physics Department. In 1941-42 he taught physics courses in the Berkeley Physics Department. He taught upper-division optics, quantum mechanics, atomic physics, graduate thermodynamics and statistical mechanics. In 1943 he accepted an invitation from Oppenheimer to join the Los Alamos group. From 1943 to 1946 he was a group leader in the Los Alamos National Laboratory. He was working on the Manhattan Project. He was the leader of the radioactivity group. Their discovery of spontaneous fission of plutonium had a far- reaching consequence on this project. It led to the reorganization of the Los Alamos laboratory in the summer of 1944. Edward Teller, Enrico Fermi, David Bohm, Robert Oppenheimer, Neils Bohr, James Franck Leo Szilard and Klaus Fuchs were the other famous scientists involved in this project, which developed the atom bombs, which were dropped on Hiroshima and Nagasaki. In 1944 he also became a naturalized citizen of the USA. In 1946 he returned to the University of California in Berkley as a Professor in the Physics Department and remained there till 1972. After he returned to Berkeley he taught the under graduates fairly regularly. He taught quantum mechanics and nuclear physics courses. In the course of his career at Berkeley he was responsible for training thirty Ph. D students. Although he retired in 1972 he spent his time traveling and writing. In subsequent years even after his retirement he continued to lecture from time to time on historical topics in an undergraduate special course. In 1974 he returned to the University of Rome and became a Professor of Nuclear Physics.

His work

Professor Segre worked mainly in atomic and nuclear physics. In atomic physics he worked on atomic spectroscopy. He made useful contributions to the spectroscopy of forbidden lines and the study of the Zeeman effect. During this period he also did some work on molecular beams.

In 1934 he began his research in nuclear physics collaborating with Professor Fermi on neutron research. This work included experiments where elements such as uranium were bombarded with neutrons and elements heavier than uranium were created. In 1935 they discovered slow neutrons, which have properties important for the operation of nuclear reactors. Thus pioneering neutron work carried out in Rome between 1934 and 1935.

He was also interested in radiochemistry. After a visit to Ernest O. Lawrence’s Berkley Radiation Laboratory he was sent a strip of molybdenum strip from the Lab’s cyclotron deflector. This was emitting anomalous forms of radioactivity. After careful chemical and theoretical analysis Segre was able to prove that some of the radiation came from a previously unknown element, which he named technetium. Thus in 1937 he discovered the new element technetium (atomic number Z = 43 ) together with the Palermo chemist Carlo Perrier. This was the first artificially synthesized element that does not occur naturally in nature since all its isotopes are unstable. In 1940 while at Berkley with Corson he discovered the element astatine. He discovered plutonium –239 and its fission properties with Kennedy, Seaborg and Wahl. Plutonium –239 was used in the first atomic bomb and also in the bomb dropped at Nagasaki.

He also studied and researched on various other fields in nuclear physics like isomerism, spontaneous fission. Later on he concentrated on high-energy physics. Together with his associates and students he made contributions to the study of interactions between nucleons and on the related polarization phenomena. In 1955 together with Chamberlain, Wiegand and Ypsilantis he discovered the antiproton using the new bevatron particle accelerator. This discovery led to the discovery of many other additional antiparticles. This fetched them the Nobel Prize in 1959. This discovery also removed any lingering doubts about the particle-antiparticle symmetry of nature. His major area of research was the study of antinucleons.

The Nobel Prize

In 1959 Emilio Gino Segre received the prestigious Nobel Prize in Physics with Owen Chamberlain for their discovery of the antiproton. An antiproton is an antiparticle having the same mass as a proton but opposite in electrical charge. He now had the accolade denied to him twenty years earlier when he had discovered the first artificial element known to humankind.

Other honours

Professor Segre was a member of the National Academy of Sciences (USA). He was also a member of the Academy of Sciences at Heidelberg, Germany. He is a member of the Accademia Nazionale dei Lincei Italy. He was awarded the Hoffmann medal of the German Chemical Society. He was honoured with the Cannizaro Medal of the Italian Accademia dei Lincei. He was an Honorary Professor of San Marcos University in Peru. The University of Palermo also awarded him an honorary doctorate degree.

In 1974 the Italian parliament honoured Professor Segre by bestowing an ad hominem

Chair at the University of Rome. He served for one year before reaching the mandatory retirement age.

Teaching career

Professor Segre was a visiting professor at many of the world famous colleges. Some of the major universities, which benefited from his services, included Columbia University, New York, University of Illinois, University of Rio de Janeiro and other famous institutions.

Personal life

Emilio Segre was married to Elfriede Spiro in 1936. In 1937 their son Claudio was born in Palermo. In 1942 their daughter Amelia was born in Berkley and in 1945 their second daughter Fausta was born in Los Alamos. In 1970 his wife Elfriede died. In 1972 he married a Uruguayan friend of Elfriede. She was called Rosa Mines and was with him till his death.

Other interests
As a photographer

Emilio Segre was an avid photographer. He was a skilful amateur photographer. He took several photos documenting the major events and people who shaped the history of modern science. The American Institute of Physics named its archives of photographs of physics in his honour. It is called the Emilio Serge Visual Archives of the American Institute of Physics. After Serge’s death his wife Rosa Segre donated a large collection of photographs, which augmented the sizable collection already available with the American Institute of Physics. Thus many of his photographs are available in the archives.

As a writer and an editor

Emilio Segre has been the writer and editor of many books, textbooks, handbooks and a biography. Some of them include Experimental Nuclear Physics in 1953 and Nuclei and Particles in 1964. In 1970 he also wrote a book on his mentor and first guide Enrico Fermi: Physicist. He also wrote two books on the history of physics. They were From X rays to Quarks: Modern Physicists and their Discoveries in 1980 and From Falling Bodies to Radio Waves in 1984.

For twenty years he was the editor of the Annual Review of Nuclear Science. He also wrote his autobiography titled A Mind Always in Motion: The Autobiography of Emilio Segre.

He was a well-read man and could quote from Dante, the Latin classics, Victor Hugo or Schiller. He was an avid mountain climber and took up fly- fishing in America. He was an accomplished hunter of wild mushrooms.


Emilio Segre died on April 22, 1989. He died of a heart attack. He has left an enduring legacy in the form of his books and students who remember his immense influence in their lives and careers. His son Claudio Serge had written a book in honour of his father aptly titled Atoms, Bombs and Eskimo Kisses: A Memoir of Father and Son thus keeping alive the memory of his father.