Emilio Segrè

Emilio Gino Segrè (1 February 1905 – 22 April 1989[1]) was an Italian-American physicist and Nobel laureate, who discovered the elements technetium and astatine, and the antiproton, a subatomic antiparticle, for which he was awarded the Nobel Prize in Physics in 1959. 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.

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, named technetium, which was the first artificially synthesized chemical element that 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 nuclear bomb dropped on Nagasaki.

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 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.

Emilio Segrè
Emilio Gino Segrè

1 February 1905
Died22 April 1989 (aged 84)
CitizenshipItaly (1905–44)
United States (1944–89)
Alma materSapienza University of Rome
Known forDiscovery of antiproton, technetium, and astatine
AwardsNobel Prize in Physics (1959)
Scientific career
InstitutionsLos Alamos National Laboratory
University of California, Berkeley
University of Palermo
Sapienza University of Rome
Columbia University
Doctoral advisorEnrico Fermi
Doctoral studentsBasanti Dulal Nagchaudhuri
Thomas Ypsilantis
Herbert York
Emilio G Segrè signature

Early life

Emilio Gino Segrè was born into a Sephardic Jewish family in Tivoli, near Rome, on 1 February 1905, the son of Giuseppe Segrè, a businessman who owned a paper mill, and Amelia Susanna Treves. He had two older brothers, Angelo and Marco.[2] His uncle, Gino Segrè, was a law professor.[3] 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.[4]

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,[5] where Segrè heard lectures from notable physicists including Niels 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,[6] and, studying under Fermi, earned his laurea degree in July 1928,[7] with a thesis on "Anomalous Dispersion and Magnetic Rotation".[4]

After a stint in the Italian Army from 1928 to 1929,[4] during which he was a commissioned as a second lieutenant in the antiaircraft artillery,[8] Segrè returned to the laboratory on Via Panisperna. He published his first article, which summarised his thesis, "On anomalous dispersion in mercury and in lithium", jointly with Edoardo Amaldi in 1928, and another article with him the following year on the Raman effect.[9]

In 1930, Segrè began studying the Zeeman effect in certain alkaline metals. 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.[10][11] 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 +1/2.[12]

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.[13] In 1934, he met Elfriede Spiro, a Jewish woman whose family had come from Ostrowo in West Prussia, but had fled to Breslau when that part of 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.[14] The two were married at the Great Synagogue of Rome on 2 February 1936. He agreed with the rabbi to spend the minimal 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.[15] The couple had three children: Claudio, born in 1937, Amelia Gertrude Allegra, born in 1937, and Fausta Irene, born in 1945.[16]

Ragazzi di via Panisperna
The Via Panisperna boys in the courtyard of Rome University's Physics Institute in Via Panisperna. Left to right: Oscar D'Agostino, Segrè, Edoardo Amaldi, Franco Rasetti and Enrico Fermi.

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.[17] 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 that 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.[18] In 1947 they named it technetium, as it was the first artificially synthesized chemical element.[19][20]

Radiation Laboratory

In June 1938, Segrè paid a summer visit to California 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.[21] The Czechoslovakian crisis prompted Segrè to send for Elfriede and Claudio, as he now feared that war in Europe was inevitable.[22] In November 1938 and February 1939 they made quick trips to Mexico to exchange their tourist visas for immigration visa. Both Segrè and Elfriede held grave fears for the fate of their parents in Italy and Germany.[23]

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 (equivalent to $5,400 in 2018) a month for six months. When Lawrence learned that Segrè was legally trapped in California, he reduced Segrè's salary to $116 a month.[24][25] 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 about 10 million medical diagnostic procedures annually.[26] 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 was.[27] Working with Alexander Langsdorf, Jr., and Chien-Shiung Wu, he discovered xenon-135,[28][29] which later became important as a nuclear poison in nuclear reactors.[30]

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 particles 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 whether he could do the chemistry and, with Kenneth Ross MacKenzie, successfully isolated the new element, which is today called astatine.[31][32][33] Segrè and Wu then attempted to find the last remaining missing non-transuranic element, element 61. They had the correct technique for making it, but lacked the chemical methods to separate it.[34] He also worked with Seaborg, McMillan, Joseph W. Kennedy and Arthur C. Wahl to create plutonium-239 in Lawrence's 60-inch (150 cm) cyclotron in December 1940.[35][36]

Manhattan Project

Emilio Segre ID badge
Segrè's ID badge photo from Los Alamos

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.[37]

In late 1942, Oppenheimer asked Segrè to join the Manhattan Project at its Los Alamos Laboratory. [38] Segrè became the head of the laboratory's P-5 (Radioactivity) Group, which formed part of Robert Bacher's P (Experimental Physics) Division.[39] For security reasons, he was given the cover name of Earl Seaman.[40] He moved to Los Alamos with his family in June 1943.[41]

Segrè's group set up its equipment in a disused Forest Service cabin in the Pajarito Canyon near Los Alamos in August 1943.[42] His group's task was to measure and catalog the radioactivity of various fission products. 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.[43] 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.[42]

The group measured the activity of thorium, uranium-234, uranium-235 and uranium-238, but only had access to microgram quantities of plutonium-239.[42] 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.[44] 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 the plutonium-240 isotope.[45]

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 1944.[46] In late 1944, Segrè and Elfriede became naturalized citizens of the United States.[47] His group, now designated R-4, was given responsibility for measuring the gamma radiation from the Trinity nuclear test in July 1945.[48] The blast damaged or destroyed most of the experiments, but enough data was recovered to measure the gamma rays.[49]

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 US$5,000 (equivalent to $69,600 in 2018). 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.[50][51]

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.[52]

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.[52] The courts ultimately resolved the patent claims in the Italian scientists' favour in 1953, awarding them US$400,000 (equivalent to $3,800,000 in 2018) for the patents related to generating neutrons, which worked out to about $20,000 after legal costs. 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.[53]

After turning down offers from IBM and the Brookhaven National Laboratory, Segrè returned to Berkeley in 1952.[54] He moved his family from Berkeley to nearby Lafayette, California, in 1955.[55] Working with Chamberlain and others, he began searching for the antiproton, a subatomic antiparticle of the proton.[56] The antiparticle of the electron, the positron had been predicted by Paul Dirac in 1931[57] and then discovered by Carl D. Anderson in 1932.[58] 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 it existed.[59] Using Lawrence's Bevatron set to 6 GeV, they managed to detect conclusive evidence of antiprotons.[56][60] Chamberlain and Segrè were awarded the 1959 Nobel Prize in Physics for their discovery.[61] This was controversial, because Clyde Wiegand and Thomas Ypsilantis were co-authors of the same article, but did not share the prize.[62]

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.[63] He was one of the trustees of Fermilab from 1965 to 1968. He attended its inauguration with Laura Fermi in 1974.[64] 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.[65][63]

Elfriede died in October 1970, and Segrè married Rosa Mines in February 1972.[16] That year he reached the University of California's compulsory retirement age. He continued teaching the history of physics.[66] In 1974 he returned to the University of Rome as a professor, but served only a year before reaching the mandatory retirement age.[63] Segrè died from a heart attack at the age of 84 while out walking near his home in Lafayette.[67] 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.[63][68][16]


  1. ^ "Emilio Segrè - Facts". Nobelprize.org. Retrieved 20 April 2018.
  2. ^ Segrè 1993, pp. 2–3.
  3. ^ Segrè 1993, p. 6.
  4. ^ a b c Jackson 2002, pp. 5–6.
  5. ^ Fermi 1954, pp. 43–44.
  6. ^ Segrè 1993, pp. 44–49.
  7. ^ Segrè 1993, p. 52.
  8. ^ Segrè 1993, pp. 54–59.
  9. ^ Segrè 1993, pp. 61, 304.
  10. ^ Jackson 2002, pp. 7–8.
  11. ^ Segrè 1993, pp. 64–70.
  12. ^ Segrè 1993, pp. 86–87.
  13. ^ "Emilio Segrè – Biography". The Nobel Foundation. Retrieved 22 May 2013.
  14. ^ Segrè 1993, pp. 96–97.
  15. ^ Segrè 1993, p. 107.
  16. ^ a b c Jackson 2002, p. 7.
  17. ^ Segrè 1993, pp. 104–106.
  18. ^ Jackson 2002, pp. 9–10.
  19. ^ Segrè 1993, pp. 115–118.
  20. ^ Perrier, C.; Segrè, E. (1947). "Technetium: The Element of Atomic Number 43". Nature. 159 (4027): 24. Bibcode:1947Natur.159...24P. doi:10.1038/159024a0. PMID 20279068.
  21. ^ Segrè 1993, pp. 128–132.
  22. ^ Segrè 1993, p. 140.
  23. ^ Segrè 1993, pp. 145–149.
  24. ^ Jackson 2002, pp. 11–12.
  25. ^ Segrè 1993, pp. 147–148.
  26. ^ Hoffman, Ghiorso & Seaborg 2000, p. 15.
  27. ^ Segrè, Emilio (June 1939). "An Unsuccessful Search for Transuranic Elements". Physical Review. 55 (11): 1103–1104. Bibcode:1939PhRv...55.1104S. doi:10.1103/PhysRev.55.1104. ISSN 0031-899X.
  28. ^ Segrè, Emilio; Wu, Chien-Shiung (March 1940). "Some Fission Products of Uranium". Physical Review. 57 (6): 552. Bibcode:1940PhRv...57..552S. doi:10.1103/PhysRev.57.552.3. ISSN 0031-899X.
  29. ^ Wu, Chien-Shiung; Segrè, Emilio (March 1945). "Radioactive Xenons". Physical Review. 67 (5–6): 142–149. Bibcode:1945PhRv...67..142W. doi:10.1103/PhysRev.67.142. ISSN 0031-899X.
  30. ^ Segrè 1993, p. 153.
  31. ^ Jackson 2002, p. 11.
  32. ^ Corson, Dale R.; MacKenzie, Kenneth Ross; Segrè, Emilio (1940). "Artificially radioactive element 85". Physical Review. 58 (8): 672–678. Bibcode:1940PhRv...58..672C. doi:10.1103/PhysRev.58.672. ISSN 0031-899X.
  33. ^ Segrè 1993, pp. 155-156.
  34. ^ Segrè 1993, pp. 155–156.
  35. ^ Seaborg, Glenn T. "An Early History of LBNL: Elements 93 and 94". Advanced Computing for Science Department, Lawrence Berkeley National Laboratory. Retrieved 17 September 2008.
  36. ^ Seaborg, Glenn T. (September 1981). "The plutonium story". Lawrence Berkeley Laboratory, University of California. OSTI 5808140. LBL-13492, DE82 004551.
  37. ^ Segrè 1993, pp. 170–172.
  38. ^ Segrè 1993, pp. 177–180.
  39. ^ Hawkins 1961, p. 101.
  40. ^ Hoddeson et al. 1993, p. 96.
  41. ^ Segrè 1993, p. 186.
  42. ^ a b c Hoddeson et al. 1993, pp. 234–236.
  43. ^ Hawkins 1961, pp. 120–121.
  44. ^ Hoddeson et al. 1993, pp. 236–239.
  45. ^ Hoddeson et al. 1993, pp. 239–244.
  46. ^ Segrè 1993, pp. 195, 214–215.
  47. ^ Segrè 1993, pp. 204–205.
  48. ^ Hoddeson et al. 1993, p. 357.
  49. ^ Hoddeson et al. 1993, p. 375.
  50. ^ Segrè 1993, pp. 206–210.
  51. ^ Jackson 2002, p. 13.
  52. ^ a b Segrè 1993, pp. 234–239.
  53. ^ Segrè 1993, pp. 245–247.
  54. ^ Segrè 1993, p. 240.
  55. ^ Segrè 1993, p. 253.
  56. ^ a b Segre, E. (1 July 1960). "Nuclear Properties of Antinucleons". science. 132 (3418): 9–14. Bibcode:1960Sci...132....9S. doi:10.1126/science.132.3418.9. ISSN 0036-8075.
  57. ^ Dirac, P. A. M. (1931). "Quantised Singularities in the Quantum Field". Proceedings of the Royal Society. 133 (821): 2–3. Bibcode:1931RSPSA.133...60D. doi:10.1098/rspa.1931.0130.
  58. ^ Anderson, Carl D. (1933). "The Positive Electron". Physical Review. 43 (6): 491–494. Bibcode:1933PhRv...43..491A. doi:10.1103/PhysRev.43.491.
  59. ^ Segrè 1993, pp. 255–257.
  60. ^ Segrè, Emilio (11 December 1959). "Properties of antinucleons – Nobel Lecture" (PDF). The Nobel Foundation. Retrieved 31 May 2013.
  61. ^ "The Nobel Prize in Physics 1959". The Nobel Foundation. Retrieved 31 May 2013.
  62. ^ Jackson 2002, pp. 15–16.
  63. ^ a b c d "Emilio Gino Segrè January 30, 1905–April 22, 1989". National Academy of Sciences biography. Retrieved 2 June 2013.
  64. ^ Segrè 1993, pp. 284–287.
  65. ^ Jackson 2002, pp. 17, 25.
  66. ^ Segrè 1993, p. 288.
  67. ^ Flint, Peter (24 April 1989). "Dr. Emilio G. Segre Is Dead at 84; Shared Nobel for Studies of Atom". The New York Times. Retrieved 31 May 2013.
  68. ^ "Photos of physicists, astronomers and other scientists – Emilio Segrè Visual Archives". American Institute of Physics. Retrieved 13 March 2012.



Further reading

External links

Alfred O. C. Nier

Alfred Otto Carl Nier (May 28, 1911 – May 16, 1994) was an American physicist who pioneered the development of mass spectrometry. He was the first to use mass spectrometry to isolate uranium-235 which was used to demonstrate that 235U could undergo fission and developed the sector mass spectrometer configuration now known as Nier-Johnson geometry.


The antiproton,
, (pronounced p-bar) is the antiparticle of the proton. Antiprotons are stable, but they are typically short-lived, since any collision with a proton will cause both particles to be annihilated in a burst of energy.

The existence of the antiproton with −1 electric charge, opposite to the +1 electric charge of the proton, was predicted by Paul Dirac in his 1933 Nobel Prize lecture. Dirac received the Nobel Prize for his previous 1928 publication of his Dirac equation that predicted the existence of positive and negative solutions to the Energy Equation () of Einstein and the existence of the positron, the antimatter analog to the electron, with positive charge and opposite spin.

The antiproton was first experimentally confirmed in 1955 at the Bevatron particle accelerator by University of California, Berkeley physicists Emilio Segrè and Owen Chamberlain, for which they were awarded the 1959 Nobel Prize in Physics. In terms of valence quarks, an antiproton consists of two up antiquarks and one down antiquark (uud). The properties of the antiproton that have been measured all match the corresponding properties of the proton, with the exception that the antiproton has electric charge and magnetic moment that are the opposites of those in the proton. The questions of how matter is different from antimatter, and the relevance of antimatter in explaining how our universe survived the Big Bang, remain open problems—open, in part, due to the relative scarcity of antimatter in today's universe.

Berta Karlik

Berta Karlik was an Austrian physicist. She worked for the University of Vienna, eventually becoming the first female professor at the institution. While working with Ernst Foyn she published a paper on the radioactivity of seawater.

She discovered that the element 85 astatine is a product of the natural decay processes. The element was first synthesized in 1940 by Dale R. Corson, K. R. MacKenzie, and Emilio Segrè, after several scientists in vain searched for it in radioactive minerals.


The Bevatron was a particle accelerator — specifically, a weak-focusing proton synchrotron — at Lawrence Berkeley National Laboratory, U.S., which began operating in 1954. The antiproton was discovered there in 1955, resulting in the 1959 Nobel Prize in physics for Emilio Segrè and Owen Chamberlain. It accelerated protons into a fixed target, and was named for its ability to impart energies of billions of eV. (Billions of eV Synchrotron.)

Carlo Perrier

Carlo Perrier (7 July 1886 – 22 May 1948) was an Italian mineralogist who did extensive research on the element technetium in 1936. He discovered the element along with his colleague, Emilio Segrè (1905-1989), in 1937.

Clyde Wiegand

Clyde Wiegand (May 23, 1915, Long Beach, Washington – July 5, 1996) was an American physicist.He was best known for the co-discovery of the antiproton in 1955, along with Owen Chamberlain, Emilio Segrè, and Thomas Ypsilantis. He was also a large contributor to the research of the atomic bomb.

He died at his home in Oakland, California of prostate cancer, aged 81.

George Placzek

George Placzek (native name: Georg Placzek) (September 26, 1905 – October 9, 1955) was a Czech physicist.Placzek was born in Brno, Moravia, then part of Austria-Hungary, into a wealthy Jewish family. He studied physics in Prague and Vienna. In the 1930s, Placzek was known as an adventurous person with sharp sense of humor, a tireless generator of novel physics ideas which he generously shared with his colleagues. The scope of Placzek's pilgrimage around world's physics centers in the 1930s was unique among his colleagues. He worked with Hans Bethe, Edward Teller, Rudolf Peierls, Werner Heisenberg, Victor Weisskopf, Enrico Fermi, Niels Bohr, Lev Landau, Edoardo Amaldi, Emilio Segrè, Otto Frisch, Leon van Hove and many other prominent physicists of his time. His wife, Els Placzek (née Andriesse) was an ex-wife of physicist Hans von Halban. He lost all his relatives to Holocaust, casting a tragic shadow on his life. Placzek's major areas of scientific work involved a fundamental theory of Raman scattering, molecular spectroscopy in gases and liquids, neutron physics and mathematical physics. Together with Otto Frisch, he suggested a direct experimental proof of nuclear fission. Together with Niels Bohr and others, he was instrumental in clarifying the role of Uranium 235 for the possibility of nuclear chain reaction.During his stay in Landau's circle in Kharkiv around 1937, Placzek witnessed the brutal reality of Joseph Stalin's regime. His first-hand experience of this influenced the political opinions of his close friends, in particular, fathers of nuclear and thermonuclear bombs, Robert Oppenheimer and Edward Teller. Later, Placzek was the only Czech with a leading position in the Manhattan project, where he worked from 1943 till 1946 as a member of the British Mission; first in Canada as the leader of a theoretical division at the Montreal Laboratory and then (since May 1945) in Los Alamos, later replacing his friend Hans Bethe as the leader of the theoretical group. Since 1948, Placzek was a member of the Institute for Advanced Study in Princeton, USA.

Unlike many trailblazers of nuclear physics, George Placzek did not leave his recollections or life story notes. Many new facts about Placzek's life and his family roots emerged in connection with a Symposium held in Placzek's memory.

Placzek's premature death in a hotel in Zurich was very likely a suicide influenced by his long-time serious illness. The first detailed biography of George Placzek sheds light on poorly known pages of his life, illuminating also circumstances of Placzek's death.

Golden age of physics

A golden age of physics appears to have been delineated for certain periods of progress in the physics sciences, and this includes the previous and current developments of cosmology and astronomy. Each "golden age" introduces significant advancements in theoretical and experimental methods. Discernible time periods marking a "golden age" of advancements are, for example, the development of mechanics under Galileo (1564–1642) and Newton (1642–1727). Another small epoch seen as a golden age is the unification of electricity, magnetism, and optics because of 19th century notables, including Faraday, Maxwell, and others.Significant advancements in methods of investigation were introduced for celestial mechanics, which includes realizing a universal gravitational force, with the introduction of the telescope. Basing mechanics on experimental results was possible with the development of devices that could measure time, and tools for measuring distance. The advances in electromagnetism in the 19th century enamored physicists, as another golden age closed, and there was a reluctance to perceive further advancement. Hence, the progress of one era, termed a "golden age" has appeared to mark the completion of physics as a science. Yet, this perception has turned out to be erroneous. For example, around 1980, Stephen Hawking predicted the end of theoretical physics within 20 years. Around 2001, he amended his prediction to twenty years more from that year. Steven Weinberg predicts a unified physics by 2050. Tadeusz Lulek, Barbara Lulek, and A. Wal – the authors of a 2001 book – believed themselves to be at the beginning of a new "golden age of physics".Paul Davies notes that whilst "many elderly scientists" may regard the first 30 years of the 20th century as a golden age of physics, historians may well, instead, regard it to be the dawning days of "the New Physics".The golden age of physics was the 19th century. According to Emilio Segrè, in Italy it came to an end in the 18th century, after the time of Alessandro Volta. He reported in his autobiography that Enrico Fermi felt that it was coming to an end in 1933. A golden age of physics began with the simultaneous discovery of the principle of the conservation of energy in the mid-19th century. A golden age of physics was the years 1925 to 1927. The golden age of nonlinear physics was the period from 1950 to 1970, encompassing the Fermi–Pasta–Ulam–Tsingou problem and others. This followed the golden age of nuclear physics, which had spanned the two decades from the mid-1930s to the mid-1950s. A golden age of physics started at the end of the 1920s.The golden age of physics cabinets was the 18th century, with the rise of such lecturer-demonstrators as John Keill, John Theophilus Desaguliers, and William Whiston, who all invented new physics apparatus for their lectures.

Henry Stapp

Henry Pierce Stapp (born March 23, 1928 in Cleveland, Ohio) is an American mathematical physicist, known for his work in quantum mechanics, particularly the development of axiomatic S-matrix theory, the proofs of strong nonlocality properties, and the place of free will in the "orthodox" quantum mechanics of John von Neumann.

Kenneth Ross MacKenzie

Kenneth Ross MacKenzie (June 15, 1912 – July 4, 2002) together with Dale R. Corson and Emilio Segrè, synthesized the element astatine, in 1940. MacKenzie received his PhD under Ernest Lawrence at Lawrence Livermore National Laboratory. Lawrence, MacKenzie, and their colleagues devised the first cyclotron. He was a professor of physics at UCLA, where he and Reg Richardson built UCLA's first cyclotron and later a bevatron. MacKenzie devised MacKenzie buckets which are plasma sources created by lining vacuum chamber walls with permanent magnets of alternating polarity to suppress plasma electron losses, that are widely used to this day. He later traveled around the world, helping to troubleshoot various country's cyclotron problems. Later in life, he studied plasma physics and dark matter.

As an actor, he played minor roles with Yvonne De Carlo in Ride the Pink Horse (1947), River Lady (1948) and Black Bart (1948).He died in Los Angeles on 4 July 2002 at aged 90.

Leon Mestel

Leon Mestel (5 August 1927 – 15 September 2017) was a British astronomer and astrophysicist and Emeritus Professor at the University of Sussex. His research interests were in the areas of star formation and structure, especially stellar magnetism and astrophysical magnetohydrodynamics. He was awarded both the Eddington Medal (1993) and the Gold Medal of the Royal Astronomical Society (for Astronomy, 2002). Following his retirement, he wrote several obituaries and biographical articles on physicists and astrophysicists.

Orso Mario Corbino

Orso Mario Corbino (30 April 1876, Augusta – 23 January 1937, Rome) was an Italian physicist and politician. He served as the minister for education in 1921 and as the minister for economy in 1921. He also served as professor in Messina (1905) and in Rome (1908). He is noted for his studies of the influence of external magnetic fields on the motion of electrons in metals and he discovered the Corbino effect. Corbino worked with Damiano Macaluso where they discovered the Macaluso-Corbino effect, a strong magneto-rotation of the plane of polarization observed at wavelengths close to an absorption line of the material through which the light is travelling.

As director of the Institute of physics he was the supervisor of Enrico Fermi, Edoardo Amaldi, Franco Rasetti and Emilio Segrè, Bruno Pontecorvo, Oscar D'Agostino, Ettore Majorana.

Owen Chamberlain

Owen Chamberlain (July 10, 1920 – February 28, 2006) was an American physicist, and Nobel laureate in physics for his discovery, with collaborator Emilio Segrè, of the antiproton, a sub-atomic antiparticle.

Plunkett Lake Press

Plunkett Lake Press is a publishing company based in Lexington, Massachusetts. It was founded by Patrick Mehr in 2010. PLP e-publishes classics of non-fiction: biographies, memoirs and texts of historical interest with a focus on Central Europe, such as Under a Cruel Star by Heda Margolius Kovaly and Defying Hitler by Sebastian Haffner.

PLP e-publishes literary non-fiction about several topics, including France, Germany, Israel, immigration, and science. Most Plunkett Lake Press eBooks are in English; some are in French and German. A few titles are also available in paperback. Plunkett Lake Press's eBooks are available worldwide in the Amazon/Kindle, Apple iBooks, Nook and Kobo formats.Plunkett Lake Press offers a roster of non-fiction by Stefan Zweig, including his autobiography The World of Yesterday and his biographies of Balzac, Erasmus of Rotterdam, Joseph Fouché, Magellan, Marie Antoinette, Freud, and Mary Stuart.Other Plunkett Lake Press authors include Jean-Denis Bredin, Abba Eban, Amos Elon, Albert Memmi, Susan Quinn, Emilio Segrè and Chaim Weizmann.

Robert Cornog

Robert Alden Cornog (July 7, 1912 – July 17, 1998), was a physicist and engineer who helped develop the atomic bomb and missile systems from the Snark to the Minuteman.

A native of Portland, Oregon, who grew up in Iowa City, Cornog earned a bachelor's degree in mechanical engineering at the University of Iowa. After working for the United States Bureau of Reclamation on the Boulder Dam design, he studied at UC Berkeley for his doctorate in physics.

His graduate student research led to the co-discovery, with Luis Alvarez, of hydrogen and helium of atomic mass 3 (tritium and helium-3). He also assisted Emilio Segrè in the discovery of element 85, astatine.During World War II, Cornog designed magnetic equipment for ships and went to work on the Manhattan Project, successively at UC Berkeley, Princeton University and in Los Alamos, New Mexico. Cornog became chief engineer of the ordnance division of the atomic bomb development team and was involved in the development of the bomb's trigger mechanism.In the 1950s, he focused on aerodynamics, nuclear energy and rocket engineering, working on missile systems for several Southern California companies, including Northrop, Space Technology Laboratories and Ramo-Wooldridge Corporation, which became TRW. Also an expert on vacuum technology, Cornog headed Vacuum Enterprises from 1967 to 1974 and managed product development for Torr Vacuum Products until 1984. He held several patents and served as a technical advisor on the film Fat Man and Little Boy, about the atomic bomb.

Envisioning peaceful uses for nuclear and space technology, Cornog in 1959 foresaw a world in 40 to 50 years with worldwide color television broadcasts, satellites assembled in space and accurate weather prediction.

Cornog was a close associate of rocket pioneer and occultist Jack Parsons. Science fiction author Robert A. Heinlein, a friend, dedicated his novel Stranger in a Strange Land to Cornog. Donald Kingsbury dedicated his novel The Moon Goddess and the Son to several people including "Robert Cornog for discussing the economics of the leoport."

Science and technology in Italy

Science and technology in Italy has a long presence, from the Roman era and the Renaissance. Through the centuries, Italy has advanced the scientific community which produced many significant inventions and discoveries in biology, physics, chemistry, mathematics, astronomy and the other sciences.

Thomas Ypsilantis

Thomas John Ypsilantis (Greek: Θωμάς Υψηλάντης; June 24, 1928 – August 16, 2000) was an American physicist of Greek descent. Ypsilantis was known for the co-discovery of the antiproton in 1955, along with Owen Chamberlain, Emilio Segrè, and Clyde Wiegand. Following this work, he moved to CERN to develop Cherenkov radiation detectors for use in particle physics.

Timeline of particle physics

The timeline of particle physics lists the sequence of particle physics theories and discoveries in chronological order. The most modern developments follow the scientific development of the discipline of particle physics.

Via Panisperna boys

The Via Panisperna boys (Italian: I ragazzi di Via Panisperna) were a group of young scientists led by Enrico Fermi. In Rome in 1934, they made the famous discovery of slow neutrons which later made possible the nuclear reactor, and then the construction of the first atomic bomb.

The nickname of the group comes from the address of the Physics Institute, at the University of Rome La Sapienza. The Via Panisperna, a street of Rione Monti in the city center, got its name from a nearby monastery, San Lorenzo in Panisperna.

The other members of the group were Edoardo Amaldi, Oscar D'Agostino, Ettore Majorana, Bruno Pontecorvo, Franco Rasetti and Emilio Segrè. All of them were physicists, except for D'Agostino who was a chemist.

Related topics
Military installations
See also

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.