Emilio G . Segrè Emilio Gino Segrè ( 30 January 1905 – 22 April 1989 ) was an Italian physicist and Nobel laureate who discovered the elements technetium and astatine , and the antiproton , a sub - atomic antiparticle , for which he was awarded the in Nobel Prize in Physics in 1959 . Born in Tivoli , near Rome , Segrè studied engineering at the University of Rome La Sapienza before taking up physics in 1927 . Segrè was appointed assistant professor of physics at the University of Rome in 1932 and worked there until 1936 , becoming one of the Via Panisperna boys . From 1936 to 1938 he was Director of the Physics Laboratory at the University of Palermo . After a visit to Ernest O . Lawrence ' s Berkeley Radiation Laboratory , he was sent a molybdenum strip from the laboratory ' s cyclotron deflector in 1937 which was emitting anomalous forms of radioactivity . After careful chemical and theoretical analysis , Segrè was able to prove that some of the radiation was being produced by a previously unknown element , dubbed technetium , which was the first artificially synthesized chemical element which does not occur in nature . In 1938 , Benito Mussolini ' s fascist government passed anti - Semitic laws barring Jews from university positions . As a Jew , Segrè was now rendered an indefinite émigré . At the Berkeley Radiation Lab , Lawrence offered him a job as a Research Assistant . While at Berkeley , Segrè helped discover the element astatine and the isotope plutonium - 239 , which was later used to make the Fat man atomic bomb dropped on Nagasaki . From 1943 to 1946 he worked at the Los Alamos National Laboratory as a group leader for the Manhattan Project . He found in April 1944 that Thin Man , the proposed plutonium gun - type nuclear weapon would not work because of the presence of plutonium - 240 impurities . In 1944 , he became a naturalized citizen of the United States . On his return to Berkeley in 1946 , he became a professor of physics and of the history of science , serving until 1972 . Segrè and Owen Chamberlain were co - heads of a research group at the Lawrence Radiation Laboratory that discovered the antiproton , for which the two shared the 1959 Nobel Prize in Physics . Segrè was also active as a photographer , and took many photos documenting events and people in the history of modern science , which were donated to the American Institute of Physics after his death . The American Institute of Physics named its photographic archive of physics history in his honor . Early life . Emilio Gino Segrè was born into a Sephardic Jewish family in Tivoli , near Rome , on 30 January 1905 , the son of Giuseppe Segrè , a businessman who owned a paper mill , and Amelia Sussanna Treves . He had two older brothers , Angelo and Marco . His uncle , Gino Segrè , was a law professor . He was educated at the " ginnasio " in Tivoli , and , after the family moved to Rome in 1917 , the " ginnasio " and " liceo " in Rome . He graduated in July 1922 , and enrolled in the University of Rome La Sapienza as an engineering student . In 1927 , Segrè met Franco Rasetti , who introduced him to Enrico Fermi . The two young physics professors were looking for talented students . They attended the Volta Conference at Como in September 1927 , where Segrè heard lectures from notable physicists including Neils Bohr , Werner Heisenberg , Robert Millikan , Wolfgang Pauli , Max Planck and Ernest Rutherford . Segrè then joined Fermi and Rasetti at their laboratory in Rome . With the help of the director of the Institute of Physics , Orso Mario Corbino , Segrè was able to transfer to physics , and , studying under Fermi , earned his laurea degree in July 1928 , with a thesis on " Anomalous Dispersion and Magnetic Rotation " . After a stint in the Italian Army from 1928 to 1929 , during which he was a commissioned as a second lieutenant in the antiaircraft artillery , Segrè returned to the laboratory on Via Panisperna . He published his first paper , which summarised his thesis " On anomalous dispersion in mercury and in lithium " , jointly with Edoardo Amaldi in 1928 , and another paper with him the following year on the Raman effect . In 1930 , Segrè began studying the Zeeman effect in certain alkaline metal s . When his progress stalled because the diffraction grating he required to continue was not available in Italy , he wrote to four laboratories elsewhere in Europe asking for assistance , and received an invitation from Pieter Zeeman to finish his work at Zeeman ' s laboratory in Amsterdam . Segrè was awarded a Rockefeller Foundation fellowship , and , on Fermi ' s advice , elected to use it to study under Otto Stern in Hamburg . Working with Otto Frisch on space quantization produced results that apparently did not agree with the current theory ; but Isidor Isaac Rabi showed that theory and experiment were in agreement if the nuclear spin of potassium was + ½ . Physics professor . Segrè was appointed assistant professor of physics at the University of Rome in 1932 and worked there until 1936 , becoming one of the Via Panisperna boys . In 1934 , he met Elfriede Spiro , a Jewish woman whose family had come from Ostrowo in East Prussia , but had fled to Breslau when East Prussia became part of Poland after World War I . After the Nazi Party came to power in Germany in 1933 , she had emigrated to Italy , where she worked as a secretary and an interpreter . At first she did not speak Italian well , and Segrè and Spiro conversed in German , in which he was fluent . The two were married at the Great Synagogue of Rome on 2 February 1936 . He agreed with the rabbi to spend the minimum amount on the wedding , giving the balance of what would be spent on a luxury wedding to Jewish refugees from Germany . The rabbi managed to give them many of the trappings of a luxury wedding anyway . The couple had three children : Claudio , born in 1937 , Amelia Gertrude Allegra , born in 1937 , and Fausta Irene , born in 1945 . After marrying , Segrè sought a stable job , and became professor of physics and director of the Physics Institute at the University of Palermo . He found the equipment there primitive and the library bereft of modern physics literature , but his colleagues at Palermo included the mathematicians Michele Cipolla and Michele De Franchis , the mineralogist Carlo Perrier and the botanist Luigi Montemartini . In 1936 he paid a visit to Ernest O . Lawrence ' s Berkeley Radiation Laboratory , where he met Edwin McMillan , Donald Cooksey , Franz Kurie , Philip Abelson and Robert Oppenheimer . Segrè was intrigued by the radioactive scrap metal that had once been part of the laboratory ' s cyclotron . In Palermo , this was found to contain a number of radioactive isotopes . In February 1937 , Lawrence sent him a molybdenum strip which was emitting anomalous forms of radioactivity . Segrè enlisted Perrier ' s help to subject the strip to careful chemical and theoretical analysis , and they were able to prove that some of the radiation was being produced by a previously unknown element . In 1947 they dubbed it technetium , as it was the first artificially synthesized chemical element . Radiation Laboratory . In June 1938 , Segrè paid a summer visit to California in order to study the short - lived isotopes of technetium , which did not survive being mailed to Italy . While Segrè was " en route " , Benito Mussolini ' s fascist government passed racial laws barring Jews from university positions . As a Jew , Segrè was now rendered an indefinite émigré . The Czechoslovakian crisis prompted Segrè to send for Elfriede and Claudio , as he now feared that war in Europe was inevitable . In November 1938 and February 1939 they made quick trips to Mexico to exchange their tourist visas for immigration ones . Both Segrè and Elfriede held grave fears for the fate of their parents in Italy and Germany . : ) At the Berkeley Radiation Lab , Lawrence offered Segrè a job as a research assistant — a relatively lowly position for someone who had discovered an element — for US $ 300 a month for six months . However , when Lawrence learned that Segrè was legally trapped in California , he reduced Segrè ' s salary to US $ 116 a month . Working with Glenn Seaborg , Segrè isolated the metastable isotope technetium - 99m . Its properties made it ideal for use in nuclear medicine , and it is now used in some ten million medical diagnostic procedures annually . Segrè went looking for element 93 but did not find it , as he was looking for an element chemically akin to rhenium instead of a rare earth element , which is what element 93 turned out to be . Working with Alexander Langsdorf , Jr . , and Chien - Shiung Wu , he discovered xenon - 135 , which later became important as a nuclear poison in nuclear reactors . Segrè then turned his attention to another missing element on the periodic table , element 85 . After he announced how he intended to create it by bombarding bismuth - 209 with alpha particle s at a Monday meeting Radiation Laboratory meeting , two of his colleagues , Dale R . Corson and Robert A . Cornog carried out his proposed experiment . Segrè then asked if he could do the chemistry , and , with Kenneth Ross MacKenzie successfully isolated the new element , which is today called astatine . Segrè and Wu then attempted to find the last remaining missing non - transuranic element , element 61 . They had the right technique for making it , but lacked the chemical techniques to separate it . He also worked with Seaborg , McMillan , Joseph W . Kennedy and Arthur C . Wahl to create plutonium - 239 in Lawrence ' s cyclotron in December 1940 . Manhattan Project . The Japanese attack on Pearl Harbor in December 1941 , and the subsequent United States declaration of war upon Italy , rendered Segrè an enemy alien , and cut him off from communication with his parents . Physicists began leaving the Radiation Laboratory to do war work , and Raymond T . Birge asked him to teach classes to the remaining students . This provided a useful supplement to Segrè ' s income , and he established important friendships and professional associations with some of these students , who included Owen Chamberlain and Clyde Wiegand . In late 1942 , Oppenheimer asked Segrè to join the Manhattan Project at its Los Alamos Laboratory . Segrè ' s group set up its equipment in a disused Forest Service cabin in the Pajarito Canyon near Los Alamos in August 1943 . His group ' s task was to measure and catalog the radioactivity of various fission product s . An important line of research was determining the degree of isotope enrichment achieved with various samples of enriched uranium . Initially , the tests using mass spectrometry , used by Columbia University , and neutron assay , used by Berkeley , gave different results . Segrè studied Berkeley ' s results and could find no error , while Kenneth Bainbridge likewise found no fault with New York ' s . However , analysis of another sample showed close agreement . Higher rates of spontaneous fission were observed at Los Alamos , which Segrè ' s group concluded were due to cosmic rays , which were more prevalent at Los Alamos due to its high altitude . The group measured the activity of thorium , uranium - 234 , uranium - 235 and uranium - 238 , but only had access to microgram quantities of plutonium . The first sample plutonium produced in the nuclear reactor at Oak Ridge was received in April 1944 . Within days the group observed five times the rate of spontaneous fission as with the cyclotron - produced plutonium . This was not news that the leaders of the project wanted to hear . It meant that Thin Man , the proposed plutonium gun - type nuclear weapon , would not work , and implied that the project ' s investment in plutonium production facilities at the Hanford Site was wasted . Segrè ' s group carefully checked their results and concluded that the increased activity was due to plutonium - 240 . In June 1944 , Segrè was summoned into Oppenheimer ' s office and informed that while his father was safe , his mother had been rounded up by the Nazis in October 1943 . Segrè never saw either of his parents again . His father died in Rome in October 1943 . In late 1944 , Segrè and Elfriede became naturalized citizens of the United States . His group , now designated R - 4 , was given responsibility for measuring the gamma radiation from the Trinity nuclear test in July 1945 . The blast damaged or destroyed most of the experiments , but enough data was recovered to measure the gamma rays . Later life . In August 1945 , a few days before the surrender of Japan and the end of World War II , Segrè received an offer from Washington University in St . Louis of an associate professorship with a salary of $ 5 , 000 . The following month , the University of Chicago also made him an offer . After some prompting , Birge offered $ 6 , 500 and a full professorship , which Segrè decided to accept . He left Los Alamos in January 1946 , and returned to Berkeley . In the late 1940s , many academics left the University of California , lured away by higher salary offers , and by the University ' s peculiar loyalty oath requirement . Segrè chose to take the oath and stay , but this did not allay suspicions about his loyalty . Luis Alvarez was incensed that Amaldi , Fermi , Pontecorvo , Rasetti and Segrè had chosen to pursue patent claims against the United States for their pre - war discoveries , and told Segrè to let him know when Pontecorvo wrote from Russia . He also clashed with Lawrence over the latter ' s plan to create a rival nuclear weapons laboratory to Los Alamos in Livermore , California , in order to develop the hydrogen bomb , a weapon that Segrè felt would be of dubious utility . Unhappy with his deteriorating relationships with his colleagues , and with the poisonous political atmosphere at Berkeley caused by the loyalty oath controversy , Segrè accepted a job offer from the University of Illinois at Urbana – Champaign . The courts ultimately resolved the patent claims in the Italian scientists ' favour in 1953 , awarding them $ 400 , 000 for the patents related to generating neutrons , which worked out to about $ 20 , 000 after each of the lawyers took his or her cut . Kennedy , Seaborg , Wahl and Segrè were subsequently awarded the same amount for their discovery of plutonium , which came to $ 100 , 000 after being divided four ways , there being no legal fees this time . After turning down offers from IBM and the Brookhaven National Laboratory , Segrè returned to Berkeley in 1952 . He moved his family from Berkeley to nearby Lafayette , California , in 1955 . Working with Chamberlain and others , he began searching for the antiproton s , a sub atomic antiparticle of the proton . The antiparticle of the electron , the positron had been predicted by Paul Dirac in 1931 . and then discovered by Carl D . Anderson in 1932 . By analogy , it was now expected that there would be an antiparticle corresponding to the proton , but no one had found one , and even in 1955 some scientists doubted that they existed . Using Lawrence ' s bevatron set to 6GeV , they managed to detect conclusive evidence of antiprotons . Chamberlain and Segrè were awarded the 1959 Nobel Prize in Physics for their discovery . This was controversial , because Clyde Wiegand and Thomas Ypsilantis were co - authors of the same paper , but did not share the prize . Segrè served on the University ' s powerful Budget Committee from 1961 to 1965 , and was chairman of the Physics Department from 1965 to 1966 . He supported Teller ' s successful bid to separate the Lawrence Berkeley Laboratory from the Lawrence Livermore Laboratory in 1970 . He was one of the trustees of Fermilab from 1965 to 1968 . He attended its inauguration with Laura Fermi in 1974 . During the 1950s , Segrè edited Fermi ' s papers . He later published a biography of Fermi , " Enrico Fermi : Physicist " ( 1970 ) . He published his own lecture notes as " From X - rays to Quarks : Modern Physicists and Their Discoveries " ( 1980 ) and " From Falling Bodies to Radio Waves : Classical Physicists and Their Discoveries " ( 1984 ) . He also edited the Annual Review of Nuclear and Particle Science from 1958 to 1977 , and wrote an autobiography , " A Mind Always in Motion " ( 1993 ) , which was published posthumously . Elfriede died in October 1970 , and Segrè married Rosa Mines in February 1972 . That year he reached the University of California ' s compulsory retirement age . He continued teaching the history of physics . In 1974 he returned to the University of Rome as a professor , but served only a year before reaching the mandatory retirement age . Segrè died of a heart attack at the age of 84 while out walking near his home in Lafayette . Active as a photographer , Segrè took many photos documenting events and people in the history of modern science . After his death Rosa donated many of his photographs to the American Institute of Physics , which named its photographic archive of physics history in his honor . The collection was bolstered by a subsequent bequest from Rosa after her death from an accident in Tivoli in 1997 .